Angelina Jolie stopped singing after an ex criticised her voice.

The 49-year-old actress - who was previously married to Johnny Lee Miller, Billy Bob Thornton and Brad Pitt - admitted her role as opera singer Maria Callas in biopic 'Maria' was challenging because she had to overcome her fears about airing her vocals in public.

She told The Hollywood Reporter: "It was an out-of-body experience because I don’t sing.

“I had somebody in my life who was not kind to me about singing. It was a relationship I was in. And so I just assumed I couldn’t really sing.

“I’d been to theatre school, so it was weird that it even had an effect on me. I just kind of adapted to this person’s opinion. So it took me getting past a lot of things to start singing.”

Angelina - who has Maddox, 23, Pax, 20, Zahara, 19, Shiloh, 18, and 16-year-old twins Knox and Vivienne, with Brad - recently thanked her sons for helping ease her nerves about singing in the film.

Speaking at a press conference for the movie at the Venice Film Festival last week, she said: "I was terribly nervous; I spent almost seven months training. My first time singing, I remember being so nervous. My sons were there and they helped to block the door [so] that nobody else was coming in, and I was shaky.

"And [director Pablo Larraín], in his decency, started me in a small room and ended me in La Scala. So he gave me time to grow. I was frightened to live up to [Callas]."

Angelina joked that, after making the movie, she might even get involved in karaoke nights in the future.

Asked if she has a favourite karaoke song, she quipped: "I didn't sing before this [movie] so I haven't done karaoke, but now maybe I have a few!"