Iain Lee has claimed he was sexually abuse by his scout master when he was eight years old.
The 44-year-old comic has previously spoken candidly about his struggles with depression and he has now revealed he believes his problems all stem from the horrific incident when he was a schoolboy.
Speaking on upcoming Channel 5 documentary "Me and My Mental Health", Iain said: "A lot of my depression comes around self-loathing, shame and guilt.
"How do I say this? There was a bit of sexual abuse that went on as a kid. A scout master and stuff, which kind of weighed heavily on me.
"It is the most horrendous messed-up scenario, it was humiliating and it was shameful, and I remember getting home to my mum and dad and never telling them. I never told them.
"I think it certainly played a part in my depression, what happened to me at the age of eight. I can see that as the starting point for it. Because up until then the memories I do have are generally quite happy."
And the "I'm A Celebrity... Get Me Out Of Here" finalist admitted he still feels "embarrassed and ashamed" about what happened to him.
He said: "Now I feel embarrassed and ashamed talking about it, it was 35 years ago."
Iain also spoke candidly about a time a few years ago when he had a "fantasy" about taking his own life.
He said: "I was out walking the dog and we were in these woods and I just thought, "F**k, this is really off the beaten track, I could get a bit of rope.
"I could hang myself here and no-one would find me for ages." And I really allowed myself to go off into this fantasy."