The stand-up comedian, famed for appearances on Mock The Week and Live At The Apollo, had his career dramatically screech to a halt in 2018 when he was caught kissing pro partner Katya Jones when he took part on the BBC series.
Walsh and Jones later apologised for their behaviour on Strictly spin-off It Takes Two, but they were eliminated the following week.
His stint in the ITV jungle marks his first major return to TV since.
"To be totally honest with you, my poor ex, my girlfriend at the time, posted a statement. My girlfriend [at the time] posted a statement and that was the end of me," he told his campmate.
“I said sorry. I sat on Jonathan Ross’s TV show and apologised. I sat next to will.i.am and Samuel L. Jackson and apologised.
"That will forever be the weirdest moment of my life and I have to say probably the worst moment of my life."
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Cleaver sympathised with Walsh, dubbing him a "sensitive soul" in a chat later on in the Bush Telegraph, and noted: "He’s been through the ringer the last three years. I think he’s really brave and I’m glad he’s here."
In his own confessional later on, Walsh added: "That’s something in my life that I don’t want to go back to. Obviously I knew it would come up. They come up so naturally here.
"I just want to move on. It’s really nice to have people that will listen and are so lovely and wonderful."
"I just want to be clear in that I’m very sorry about what happened and I really want [I'm A Celebrity] to be a positive experience and it really has been. I want to come out of here and move forward."
At the time of the kiss, Jones was married to fellow Strictly pro, Neil Jones, while Walsh was in a five-year relationship with Ten Percent actress Rebecca Humphries. Both split with their respective partners shortly after.
Humphries later posted a powerful statement about Walsh's treatment of her during the relationship, including "gaslighting" behaviour including calling her "crazy" when she raised her suspicions of his close relationship with Jones.
I'm A Celebrity... Get Me Out Of Here airs weeknights at 9pm on ITV.
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