In recent years, the world has seen a rapid increase in the popularity of vegan eating.
Veganism means following a diet and lifestyle that completely excludes animal products and avoids any practices that relate to animal cruelty.
In simple terms, being a vegan means you don't eat anything that comes from an animal - no meat, no dairy, no eggs and no clothing materials made from animal skin, like fur.
The vegan diet was first officially defined back in 1944 by The Vegan Society, encouraging people to use animal-free alternatives for the benefit of humans, animal welfare and the environment.
So what do vegans eat?
A vegan diet involves a plethora of tasty food stuffs, including fruit, vegetables, nuts, grains, seeds, beans and pulses.
What is the difference between a vegan and vegetarian diet?
In simple terms, vegetarians are people who don't eat meat, poultry or seafood.
But in recent decades, many many variations of the vegetarian diet have emerged including:
Vegans - total vegetarians who do not eat meat, poultry, fish or any animal products including eggs, dairy products and gelatin.
Lacto vegetarians - do not eat meat, poultry, fish or eggs, but do consume dairy products.
Ovo vegetarians - do not eat meat, poultry, fish or dairy, but do eat eggs.
Lacto-ovo vegetarians - do not eat meat, poultry or fish, but do eat eggs and dairy products.
Partial vegetarians are people who avoid meat but eat fish - known as pescatarians - or poultry - known as pollo-vegetarians.
Like vegetarians, vegans do not eat any animal flesh. But in addition to not consuming animal meat, a vegan does not eat eggs, dairy products or any other product derived - even in small part - from an animal.
So now you understand the terms and jargon, let's take a look at 26 of the world's most famous vegan celebrities!
Former heavyweight boxing champion Mike Tyson famously went vegan in 2010, choosing a plant-based lifestyle for health reasons according to The Huffington Post.
"I just felt like changing my life, doing something different. And so I became vegan," Tyson said shortly afterwards.
"Becoming a vegan, it gave me another opportunity to live a healthy life."
Former Victoria's Secret queen and Brazil's top model Gisele is a well known advocate of environmental causes and animal welfare initiatives.
The Brazilian beauty is a UN environmental ambassador and follows a vegan lifestyle, because she believes going vegan is the most sustainable and efficient methods of fighting climate change.
Bundchen even persuaded her American husband, retired NFL player Tom Brady, to take up a vegan diet.
Gisele's children Vivian Lake and Benjamin also eat plant-based diets, and the supermodel often shares photos of her little ones playing in her vegetable garden at their home in Boston.
She is one of the world's most famous vegans.
Miley Cyrus and Liam Hemsworth
Dubbed a vegan power couple by Plant Based News, Miley Cyrus and Liam Hemsworth took their dietary commitment to the next level at their low key December 2018 wedding.
The celebrity pair treated guests to a plant-based buffet of vegan and vegetarian food, and Miley even shared an Instagram with her sister Noah and Brandi with the caption: "Best part of bein' the bride ..... skippin the buffet lines! Mood forever with Noah Cyrus, Brandi Cyrus. #VeganWedding #HotNonViolentAnimalLovingHusbandsAreHottest"
Liam previously told Men's Fitness about his decision to turn vegan, saying: "After all the information I gathered about the mistreatment of animals, I couldn't continue to eat meat. The more I was aware of, the harder and harder it was to do."
Miley, meanwhile, spoke to her 83 million Instagram followers in January about her vegan lifestyle noting: "You can't say you care about animals if you eat them."
Miley, a firm believer that animals have personalities and souls, reportedly went vegan after wild coyotes killed her beloved pet dog.
In 2015, the tennis icon told Shape Magazine she feels being vegan is "a great lifestyle for long-term stability".
Venus suffers from an autoimmune disease called Sjogren's syndrome which prevents her from living vegan 100 percent of the time, but she follows a vegan diet insofar as her condition allows.
Peter Dinklage - best known for his roles as Tyrion Lannister in Game of Thrones and Bolivar Trask in X-Men - was a vegetarian for over 15 years before going vegan in 2014.
Dinklage has fronted numerous campaigns for PETA and the Farm Sanctuary - the first and largest American animal sanctuary, according to Live Kindly - as well as acting as an ambassador for Cruelty Free International.
The Golden Globe winner believes people should adopt a vegan lifestyle on ethical grounds, and has been known to refuse meat whilst filming.
Peter has advocates or adopting over buying pets from breeders, and is a "pet parent" to a dog called Kevin.
Self-proclaimed "naughty vegan" Pamela Anderson recently revealed she will never wear leather or real fur again.
Pam decided to become a vegetarian as child after finding a dead deer killed by her hunter father and has since become vocal about animal cruelty and how people can work to fight it.
In an op-ed for The Guardian newspaper, the Baywatch icon admitted she "does the best she can [with her diet]" but isn't always so strict.
She cited Stella McCartney and dad Paul McCartney's campaign Meatless Mondays as a great initiative which proves even if you eat meat-free just one day a week, you're still doing something positive for animals and for the planet.
Oscar nominated actress Jessica Chastain has followed a vegan lifestyle since 2008, and has been a vegetarian since around 1998.
Jessica previously told Healthy Celeb the reason for her dietary choice is her love of animals and how it helps her with weight loss.
Actor Casey Affleck is a longtime vegan eater, and even worked on banned PETA public service announcement which blasted the abuse of animals.
Of his reason for going vegan, Affleck has said: "When people ask me when I don't eat meat or any other animal products, I say - 'Because they are unhealthy and they are the product of a violent and inhumane industry.'"
Affleck has also been vocal about his belief that eating meat contributes to heart disease and cancer.
Ellen DeGeneres and Portia de Rossi
US talk show icon Ellen DeGeneres has been a committed vegan since 2008.
Her wife, actress Portia de Rossi, fully supports her diet and the couple are vocal advocates of animal welfare charities.
Ellen, 60, recently reposted a social media video called Animal on Earth posted by vegan Australian animal activist James Aspey to her 52.5 million followers on Instagram.
Portia previously revealed Ellen's favourite vegan dish is red beans and rice as well as pizza without cheese.
According to celebrity vegan database Veganuary, Hollywood legend Woody Harrelson is a serious advocate for eating a meat-free, animal product free diet.
He turned vegan in his early 20s when he was a struggling actor diagnosed with lactose intolerance.
Woody was named PETA's Sexiest Vegan in 2012, and he's also a huge consumer of raw food and an outspoken environmentalist.
Harrelson even invested in an organic vegan beer garden called Sage.
In March, Ariana Grande announced she was collaborating with Starbucks to create a new drink called the Cloud Macchiato, an espresso shot and milk with fluffy foam that comes in caramel or cinnamon flavour.
The ingredients of the Cloud Macchiato caused controversy because of the inclusion of butter, heavy cream and milk - meaning the beverage is not vegan.
This sparked a storm of criticism because Ariana herself has professed to follow a strictly vegan lifestyle since 2013.
In an interview with The Mirror in 2014, the Thank U Next hitmaker said she "loves animals more than people" and believes "eating a full plant-based, whole food diet...can expand your life length and make you an all-round happier person".
Charlie's Angel alum Drew Barrymore reportedly lost 25 pounds in three months thanks to ballet classes and eating a vegan diet.
Barrymore admitted she only eats vegan some of the time, like when she's shooting her Netflix show Santa Clarita Diet.
Beyoncé is another A-lister who credits going vegan for helping her to shed weight, fast.
Beyoncé and Jay-Z
In January, Vogue reported - as only Vogue can - that Beyoncé and husband Jay Z are "vegan curious".
Before her hotly anticipated Coachella headline performance in 2018, Queen B adopted a plant-based diet to whip herself into tip top shape.
A few years before that, the power couple launched a vegan meal service called 22 Days Nutrition with the help of their personal trainer and nutrition coach, Marco Borges.
Beyoncé often shares Instagram posts promoting the Greenprint Project, an initiative which aims to encourage people to incorporate parts of vegan eating into their daily routines.
Jay Z famously endorsed Meatless Mondays, and claims to eat two meat-free meals a day.
In a statement about their passion for vegan lifestyle, the parents-of-three cited veganism's carbon cutting effects and the benefits following a plant-based diet can have on human health and the environment.
Iconic soul singer Stevie Wonder famously turned vegan for environmental and compassionate reasons, and in 2015 told British comedian James Corden he felt wonderful "not eating animals" - yet admitted he does miss chicken.
According to Veganuary, Russell Brand has followed a vegetarian lifestyle since the age of 14, summing up his outlook as: "You shouldn't eat animals, it's mean to them."
After watching the 2011 documentary Forks and Knives, Russell converted to veganism before reverting to vegetarianism in 2013.
In March, Plant Based News reported the politically-minded comedian had returned to eating a vegan diet.
British singer-songwriter Morrissey - born Steven Patrick Morrissey - famously refused "to eat anything that had a mother".
He previously revealed he exists on a vegan diet of just bread, potatoes, pasta and nuts, and has sparked controversy be declaring that "vegans are superior beings".
The legendary singer, a famous animal rights advocate and longtime critic of factory farming, has admitted he follows a particularly bland diet and can't eat anything that has flavour, including "curry, coffee and garlic".
Vegan star of the Big Bang Theory Mayim Bialik has spoken about her belief that eating meat is linked to heart disease, strokes, diabetes and cancer.
Bialik is a PETA ambassador who advocates for following a plant-based diet to save animals' lives and lead a healthier existence ourselves.
In 2018, Mayim created a YouTube video where she debunked common myths about being vegan, reminding viewers that it's more than possible to get enough protein from eating tasty, meat-free food like quinoa, tofu and beans.
Oscar winning actor Jared Leto is a longterm vegetarian and more recent vegan.
When he turned 41, Leto credited his plant-based diet (as well as lots of sleep) for his youthful appearance, telling GQ Magazine: “It’s probably just down to sleep and diet. If you travel long haul a lot or don’t sleep much, it’s not going to last very long, that’s for sure. I’m pretty healthy so I think that helps a lot. I’ve been that way for a long time – 20 solid years of eating vegetarian/vegan and taking care of myself. That probably helps the preservation process.”
Leto officially refers to himself as a 'cheagan', which he says is a cheating vegan.
"I don’t eat meat ever. But if someone’s mom made a cookie and handed it to me, I’d probably take a bite, or if I’m in Alaska and there’s wild salmon out of the river, I’d probably eat it," he once told Rolling Stone.
Cowboys and Aliens star Olivia Wilde has been a vegetarian since the age of 12, according to Veganuary.
The actress has been following an almost vegan lifestyle for the past four years, except during her pregnancy when she returned to vegetarian eating.
Wilde caused controversy in the animal rights community by returning to vegetarianism after her divorce, leading many critics to say she was merely jumping on a fashionable bandwagon.
Wilde told Cosmopolitan at the time, "I actually really like healthy food. I was hardcore vegan for years. When everything in my life became a little hectic, going through the divorce and everything afterward, I was like 'I need some goddamn cheese'. And so I had some cheese."
Titanic director James Cameron is one of the world's most famous vegans.
The filmmaker is a passionate environmentalist and in 2018 helmed a documentary called The Game Changers about how a global shift towards plant based living could positively impact climate change.
Animal lover Natalie Portman is one of the world's most famous vegans.
The Black Swan star produced a documentary called Eating Animals - based on the book by Jonathan Safran Foer - which questions the practice of raising animals to slaughter for food.
Portman is also passionate about the environmental damage cause by eating meat.
Irish-born Harry Potter star Evanna Lynch has been a committed vegetarian since childhood because, as she told Vegan Food and Living, she was "viscerally repelled by the idea of eating animal flesh and there was no way to avoid the fact that someone had been killed for that piece of meat."
Evanna transitioned to a fully vegan lifestyle in 2015 after reading Jonathan Safran Foer's Eating Animals, just like Natalie Portman.
Jenna Dewan Tatum
The ex wife of Magic Mike star Channing Tatum has been a committed vegetarian from a young age, previously revealing she felt traumatised after watching a documentary about slaughterhouses age 10 or 11.
Jenna was later diagnosed as lactose intolerant which prompted her to change her diet to a vegan lifestyle.
She has credited veganism for clearing her skin, giving her "tonnes" more energy and improving her mental clarity.