Robert Carlyle thinks American actresses shy away from ''monstrous roles''.

The 54-year-old actor - who starred in 'Trainspotting' and 'The Full Monty' - has argued that Americans, unlike their British counterparts, are reluctant to take on such roles.

He said: ''You don't see too many American actresses taking on monstrous roles. You offer that sort of part to a Hollywood actress and they wouldn't want to be seen in that light.

''But any actor worth their salt should look to confound audience expectations. It's why I asked Emma Thompson to play a crazy, psychotic part in 'The Legend of Barney Thomson' [which Carlyle stars in and directs].''

According to Robert, the actress' willingness to play the part exemplified the differences between British and American performers.

He told the Independent on Sunday newspaper: ''I knew she was a brave actress - she was a beautiful woman until we got that make-up on her.

''I think that adventurousness is what differentiates Brits from Americans.''

Meanwhile, Robert also acknowledged the importance of doing extensive research before assuming a role, but denied claims he's a method actor.

He shared: ''I went homeless for a while, for 'Safe'; it gives you something extra, a little bit of knowledge you didn't have.

''I used to do a lot of preparation for roles, but once you reach a certain level of celebrity, you become the observed rather than the observer.''