James recently shared this sweet snap with his twin and their lookalike daughters, with Nick and his daughter Grace on the left and James with daughter Scout on the right.
"Cheeky monkeys," James wrote on Instagram, and his brother Nick was not far behind him in sharing the same photo to his own Instagram.
"I asked for a serious photo," he quipped in the caption.
James, who shares nine-year-old daughter Scout with ex-partner Jessica Marais, and Nick, with 11-year-old Grace, often joke about their daughters who look so alike.
"These two little ladies have got it all over us bro @__jamesstewart__," Nick shared to Instagram.
To mark their 45th birthday last year, James shared this adorable throwback pic from their childhood and said:
"Happy Birthday bro!! Still can’t tell who’s who?!🤷🏽♂️ And why did one of us miss the part the hair memo!! #twinning."
Meanwhile, Nick celebrated their shared birthday with a photo of the pair all suited up and looking smart.
"Happy birthday Twinny!!" he said.
"Annual daddy-daughter day!" both James and Nick shared to their own Instagram accounts.
The brothers took this snap from the road with Sarah Roberts, James' wife, third wheeling in the back as the twinning pair sat up in front.
Nick had also shared a screenshot from a FaceTime call he had with the couple, where he said: "Love spending this time with my family!! These two crack me up."
Another baby pic! James and Nick look even more alike in their younger years, with the Home and Away star sharing the photo on their birthday.
"BIRTHDAY POST!- 🎵”It’s your birthday... we gunna party like its yo birthday... we gunna sip Bacardi like it’s yo birthday...”🎤🎧," James captioned the post.
"Happy Birthday bro👊🏽 @__nickstewart__ #twinning."
On the day of his wedding to fellow Home and Away star Sarah, James enlisted the help of Nick when it came to putting on his bow-tie.
Nick shared the sweet moment to his Instagram and said: "She’ll make a man outta you!! 🤵🏽👰🏽"
For their sister's wedding, the dashing pair suited up and proudly posed with their two girls who were the flower girls for the event.
"Family time with Scout & Grace... Flower girls at my sisters wedding!" James said.
"Family time for our sisters wedding! Last time I wore a suit was to court," Nick joked.
While they've been together since birth - obviously - not many people know that James even has a twin, and this is something Nick addressed in a hilarious Instagram caption.
"For god sake!! Yes there’s TWO of us!! #twins #homeandaway," he said.
To celebrate their 43rd birthday, the brothers shared the same photo and each penned their own captions in dedication to one another.
"Birthday twinning.. spent all my years around the sun with this guy! Pretty awesome," James said.
"43 years around the 🌞 together!! Happy Birthday Jimzy..." Nick wrote.
"...same same but different," James quipped, whereas Nick had shared the same photo a few months earlier and wrote: "Soul time... together again!"
To celebrate Easter, the twinning foursome snapped a family photo and wrote: "Happy Easter from ours to yours!"
The brothers also took to their own Instagram accounts to share a photo of them both with their daughters, where Nick wrote:
"...can’t get enough of these two crazy kids, they think they’re more twins than their dads!!"
When worlds collide! James shared this snap of his brother meeting his work family on the set of Home and Away and wrote:
"Special visitor to the bay today.."
While fans have been treated with cute baby photos of the twins, James also shared this rare photo of him and Nick from their teenage years.
"Throwback Thursday... me and Nick, Hawaii... 1990. I've never worn leather again... promise."
Over the years, James and Nick have shed the shaggy hair and opted for a cleaner cut, which they tend to style a little differently.
While most fans will be able to tell the pair apart these days, James often admits he has trouble telling himself apart from his brother, especially when looking at their childhood photos.
"Which one am I again @__nickstewart__ ??" he quipped on Instagram.