Sir Ian McKellen finds it ''difficult'' to cry in front of the camera.

The 76-year-old actor - who's starred in a string of hit movies during his career, including 'The Hobbit' and 'X-Men' franchises - has admitted there are limitations to his talents.

He explained: ''I am trying to get better at the job.

''I know when I'm not being good, and I know what I find difficult as an actor, and I know the corners I have to cut around and I know people are better than me. But they're not me, so I have to get on with what I do.''

Sir Ian also admitted he's spent his life trying to obscure his professional weakness.

He told the Daily Telegraph newspaper: ''I tell you what's difficult for me is an overtly emotional scene where the character cries, breaks down, has a speech about his deepest feelings. If Shakespeare hasn't written it, you're going to have to drag something out from your gut and ... That's difficult.

''I don't have much experience of expressing deep, complicated emotions for the benefit of somebody else. That's not how I've gone about my [private] life.

''So when a character does that ... I suppose sometimes you come up against a block and say, 'I can't imagine what that's like.' And then you start using other little triggers and ways of stirring it all up.''