At 62 – she celebrated her most recent birthday after filming began – Marissa is this year’s oldest contestant.
She’s also arguably the most famous, having become a household name in the ’80s when she and her sisters, twins Adele and Lisa, brought aerobics to Australia, becoming well known as the Rancan Sisters.
However, Marissa tells New Idea she didn’t want to make a big deal of her celebrity status, as she feared it would make her a sitting duck.
“Some of the housemates weren’t even born when I was doing my aerobics, so I went in not telling anyone as I thought I’d be fairly safe. I felt I didn’t want to be judged by that, as it could put a target on my back.”
It’s also due to this generation gap that Marissa made a conscious effort to avoid being pigeon-holed into playing the part of mother hen of the house.
“Look, I love being around young people because I learn so much. I learned so many new words and vocab, like ‘cooked’ and ‘salty’ and ‘throwing shade’ on someone. It was hilarious!
"But I didn’t want to look like I was the person who knew everything and how to act.
"I didn’t want to come across as that. And purposely that’s why I didn’t go into the kitchen and pretend to be the mother and cook for everyone.”
One person Marissa formed an immediate connection with was mum-of-two Angela Clancy.
By day four, the pair had begun solidifying their alliance, and Marissa hopes they’ll make it all the way to the finals together, along with Hannah Campbell.
“We’re all on the same mindset. We have similar personalities and care for each other. I’d really have to focus my mind to win over Ange… you can’t even move her.
"She’s really in that zone and doesn’t let anyone get in her way, which I admire.”
Whether she manages to take home the $250,000 prize money remains to be seen, but Marissa is enjoying being back in the spotlight and admits she’s well and truly caught the reality TV bug. In fact, she’s already eyeing up her next show.
“I’d like to do more dance. If Dancing with the Stars ever happens for me, I’d be really happy … I always say, ‘Never say never to anything!’”
Sadly, for devotees of the Rancan Sisters a reunion seems unlikely. After starting their health club in 1982, the trio disbanded in 1988 when their father fell ill with cancer.
While Adele and Lisa moved into the Pilates industry, Marissa switched her attention to her “passion” – makeup.
“We’re not as close as we were. Like all families … as you grow older you drift apart. But if someone wanted to do a fitness collaboration with me, I’d never say no – fitness has always been a part of my life!”