ROSIE O'DONNELL's friendship with Madonna made her realise she didn't want to be hugely famous.

The 62-year-old actress admitted being cast in 1992's 'A League of Their Own' alongside the 'Vogue' hitmaker was "life-altering" for her because it made her reconsider what she wanted from her career as she got to see up close how "toxic" being a celebrity could be.

She explained to David Duchovny on his 'Fail Better' podcast: “To be cast in a movie opposite the most famous woman in the world as the best friend — right, me and Madonna? That was like a life-altering casting session for me because it changed my whole world.

“That kind of fame is once a generation, you know? That kind of Elvis, the Beatles, Madonna. And to be that close to it for so long and be able to get an opinion of what it does to the human being through being that close to, you know, Madonna.

“I thought that I wanted [that kind of fame]. But I thought, ‘Look at how much it takes away from her.’

"We were in an elevator, and people would say to her face, ‘I like you better with blonde hair,’ because in 'League' she had dyed her hair brown. And she'd be like, ‘Yeah, f*** you.’ You know?

“I realised how many people felt that they had the right to say whatever they wanted to her, that she had lost her humanity in the eyes of the public from being too famous.

“And it was like a cautionary tale in a way. Not that I ever thought I would achieve that level of fame, but that any level of fame could be as toxic and demanding.”

Elsewhere on the podcast, Rosie admitted she didn't realise she had to write her own jokes when she performed stand-up comedy for the first time.

The 'Exit to Eden' star was just 16 when The East Side Comedy Club owner Richie Minervini asked her to do to a set at the Long Island club after seeing her get laughs during a high school performance.

But having no act of her own, Rosie decided to mimic the then-relatively unknown Jerry Seinfeld after seeing him on 'The Merv Griffin Show'.

She admitted: “I would do his act, but not only his act, I took his cadence and his delivery."

And other comedians at the club quickly picked up on what she'd done.

She recalled: “They surround me in the back little green room and say, ‘Rosie, where’d you get that joke? I said, ‘Jerry Seinfeld.' "

When she was told she needed to write her own jokes, she defended herself by saying:“Barbra Streisand does not write her own songs. She sings other people’s songs. I’m not a writer, I’m a comedian.”