Natalie Portman has said she regrets signing a petition in support of director Roman Polanski in 2009.

The actress, who is now a prominent member of the Time’s Up movement, was one of many stars to demand the release of the film-maker, who was being held in Swiss custody on a warrant related to his 1977 under-age sex case, in which he pleaded guilty.

She told BuzzFeed: “I very much regret it. I take responsibility for not thinking about it enough.

61st Cannes Film Festival – Closing Ceremony
Roman Polanski (Joel Ryan/PA)

“Someone I respected gave it to me, and said ‘I signed this. Will you, too?’ And I was like ‘Sure’. It was a mistake.

“The thing I feel like I gained from it is empathy towards people who have made mistakes.

“We lived in a different world, and that doesn’t excuse anything. But you can have your eyes opened and completely change the way you want to live. My eyes were not open.”

Portman revealed that, after her turn in The Professional in 1996, which she filmed over her 12th birthday, the roles she was offered were “sexy little girls”.

Discussing her role in Beautiful Girls, in which she played a 13-year-old opposite Uma Thurman and Mira Sorvino, she said she feels uncomfortable about the fact that a man in his 20s, played by Timothy Hutton, falls in love with her.

Harvey Weinstein allegations
Uma Thurman also starred in Beautiful Girls (Dominic Lipinski/PA)

She said: “In retrospect it’s weird because so many of the stories around the Weinstein case involve people from Beautiful Girls.

“I didn’t know that all the adult women I was working with, who I was admiring so much and felt so cool to get to be in a movie with them, were being harassed at the same time.

“I was, like, the cute little kid on set everyone was treating totally respectfully and kindly.”

Both Thurman and Sorvino have alleged they were harassed by movie producer Harvey Weinstein.

In the same interview Portman spoke about announcing the director category at the Golden Globes by highlighting they were “all-male nominees”.

She said: “I discussed with some of the women I’ve been working with that they had offered to me to present the director category, but I felt uncomfortable because it seemed to be excluding some deserving nominees.

“And how could I bring attention to it without disrespecting the nominees? Because it’s not their fault, and they all made great work. You don’t want to not recognise them.

“It’s just, why aren’t we recognising the people who aren’t part of this exclusive club? So one of the women recommended I say that, and it felt like stating something that was true.

“That’s part of what we’re here to do. We have to make it weird for people to walk in a room where everyone’s not in the room.

“If you look around a room and everyone looks like you, get out of that room. Or change that room.

“Whether you go to a restaurant, whether you go to your kid’s school, whether you go to work – if you look around, and everyone’s not in the room, change that room.”