Sir Cliff Richard said he feared he would die of a heart attack amid the trauma caused by a 2014 police search on his home following a claim of historical sexual assault.
The veteran entertainer, who celebrated his 80th birthday this month, was never arrested and did not face any charges.
He successfully sued the BBC for its coverage of the raid.
Sir Cliff appeared on Piers Morgan’s Life Stories and opened up on the devastation caused by the incident, recalling how he was left crumpled and sobbing on the kitchen floor.
He said: “I had fallen down because what I had thought was, ‘oh my God I’m in a, in a pit, and I don’t know how to get out of this pit’.
“My career rests on it, everything, everything that I’d lived for rested on this.
“I’m thinking I could actually end in prison as an innocent man.
“And suddenly my legs just wobbled, went wobbly and I went to the floor.”
Sir Cliff told Morgan he was found by his close friend, the New York priest John McElynn.
He added: “And he — he just said to me, ‘did you do this?’
“And I said, ‘of course not’.
“He said, ‘have you ever done anything like this?’
“I went ‘absolutely not’.
“He said, ‘then I believe you, God believes you, stand up. You can do this’.”
Sir Cliff admitted he feared his career would be left in ruins by the allegation and said it took a huge toll on his health.
He said: “I was embarrassed to go out.
“I mean, I was embarrassed because I thought somebody might believe it.
“Sometimes I’d wake up, you know, in the night and I’d feel the pulses going dum-dum, in my head, my heart, and I thought I could die of a heart attack.”
Sir Cliff received around £2 million towards his legal costs from the BBC and was awarded £210,000 in damages in 2018.
After winning his action against the BBC, Sir Cliff said he felt “ultimate relief”.
He added: “That was the real end of everything.
“I was able to start smiling and feel that I’d really really got past the whole thing.”
Piers Morgan’s Life Stories airs on Sunday at 9pm on ITV.