Soap star and mother-of-three Ellison, 39, said: "Going on Celebrity SAS is like labour - you go to hell and back but then you get the most incredible reward at the end which stays with you for life. It changes you and I’ll never be the same again, I’m so thankful for the experience.”
Olympic javelin-thrower Whitbread, 61, who competed in I'm A Celebrity... Get Me Out Of Here! in 2011, said: "As a young woman I was always adventurous and living in a children’s home, I was tough and had a survival instinct, so doing Celebrity SAS is really a knock on from those days. I’d have liked to have done it as a young Whitbread, but I think I’ve flown the flag for older women!”
He said of signing up to the show: “Losing my daughter was the most difficult experience of my life. I think to combat trauma you need to step outside your comfort zone and see who you really are... so when the opportunity came, I took it with both hands!”
Reality TV brothers AJ and Curtis Pritchard will be competing against each other in the Channel 4 show, which sees celebrities endure gruelling military training as they fight it out to be the last one standing.
Strictly Come Dancing star AJ, 27, said: “It was enlightening. Everything about the show is so positive. Even in the most dangerous scenarios there’s always a positive to take from it. This was a massive life goal ticked. It was everything I hoped it would be and more.”
Younger brother, Love Island's Curtis added: "It’s seeing whether you can cope, whether you can go to hell and back and come out the other side stronger and better. I really wanted to see if I had what it takes!”
Athlete Dwain Chambers, 44, who was famously banned in 2003 for testing positive for using steroids, is also taking part.
He confessed: "I wanted to take myself out of my comfort zone, but I didn’t know what I’d let myself in for! It takes you through a series of lows that make you realise who you are. You're either somebody who crumbles under pressure, or you step up. And every single one of us stepped up. I loved every single bit of it. Would I do it again? Hell no! But I’m glad I did it.”
TOWIE's Wicks, 33, said: "I’m fortunate to have a very pampered life, so to get the chance to test what you're truly made of was an opportunity I just couldn’t turn down.”
Fellow The Only Way Is Essex star McCann, 31, revealed: “It just felt like the right time in my life to be challenged. I had no idea what to expect but I wanted to see how tough it really is. You’re stripped of everything, broken down to the point you have no choice but to build yourself back up again. It was the opportunity of a lifetime and I’m so glad I’ve done it.”
Reality star Calum Best - the 41-year-old son of footballer George Best - is another of the new recruits.
He admitted: “I’ve wanted to do this show since it started. It’s the coolest, most intriguing, entertaining show on TV because it shows people being challenged in a way you never get to see. It looked terrifying but I’d been asking for it for so long, so bring it on!”
Smith, 21, who competed in Strictly in 2020, said: "I’ve seen the show before and I really wanted to put my mental strength to the test. I’ve always pushed myself but this was beyond limits I didn’t even know I had. It was the best experience of my life..."
They are joined by Taekwondo Olympic gold medallist, Jade Jones and professional boxer Shannon Courtenay - both 29 - and 34-year-old Paralympic High Jumper, Jonathan Broom-Edwards MBE.
They will be put through their paces by ex-special forces operatives from the UK and USA - Rudy Reyes, Jason 'Foxy' Fox, Mark 'Billy' Billingham and Remi Adeleke.
Celebrity SAS: Who Dares Wins returns to Channel 4 on Sunday 4 September at 9pm for a seven-part series.
Watch: Kerry Katona on taking part in Celebrity SAS