Daniel Radcliffe and James McAvoy back Jennifer Lawrence

British actors Daniel Radcliffe and James Mcavoy have thrown their support behind Jennifer Lawrence as the row over Hollywood's gender pay gap rumbles on.

The Oscar-winning actress was mired in controversy after emails leaked from the Sony Pictures studio revealed she and Amy Adams had been paid significantly less than their male co-stars in 2013 drama American Hustle.

She recently addressed the row in an open letter in which she blamed herself for failing to fight for a higher salary, and Daniel has now spoken out about the controversy, insisting he was shocked to learn male and female stars were given such different salaries.

"The fact that the boys were on one deal and the girls were on another deal was weird," Daniel tells the Press Association. "What guy was sitting in a studio somewhere going 'Hey lets bill the girls out of some money'? The fact that that mentality still exists is slightly shocking to me."

James, who is promoting his new film Victor Frankenstein with Daniel, adds, "Jennifer kicked this thing off and I respect that lassy (woman) so much. She's proper brave..."

However, the X-Men: First Class star is adamant male workers in Hollywood should not feel pressured into disclosing their salaries.

"Maybe I should support it (Jennifer's drive) but my instinct is to go 'In what way is it wise for me to start telling you how much I earn?'..." he adds.

"There is definitely an issue and maybe it would get helped by everybody just outing what they earn. But I don't want to start putting figures on actors' heads because it's not what we do. I do realise there is a massive discrepancy with how women get paid to men, but I'm not happy telling the world how much I've got in the bank. I wouldn't be comfortable doing that as a plumber and I'm not comfortable doing it as an actor."

British actress Kate Winslet has also spoken out about the issue of women's pay in Hollywood, and she echoed James' sentiments, insisting she does not feel comfortable talking publicly about her wages.

"I understand why they are coming up but maybe it's a British thing. I don't like talking about money - it's a bit vulgar isn't it?" she told the BBC. "I don't think that's a very nice conversation to have publicly at all."