Lady GaGa was a ''total pro'' in 'Sin City: A Dame to Kill For'.

The 'Applause' singer has a cameo role in the crime thriller sequel, and Joseph Gordon-Levitt has claimed she surprised him with her talent in front of the camera.

He told radio station Jam'n 94.5: ''She was in 'Sin City 2'. I did a part for [it]. [Director Robert] Rodriguez asked me to be in, and Lady Gaga is in a scene of it. And I gotta say, she did a really good job.

''Like, she's a great actress. And I didn't know that. You know she came in and I was like, 'OK sure, they're having a huge pop star do a scene in the movie, I understand'.

''But then she came in and like, nailed it! She had her character down, and she was like a total pro and did a great job. I was really impressed.''

Fans needn't worry about Gaga being tempted by the bright lights of Hollywood though - the 'Poker Face' hitmaker has been hard at work on her upcoming album 'ARTPOP' and recently teased a new track called 'Swine'.

The star has also revealed that she wore some of Michael Jackson's old clothes while working on the record.

She previously said: ''I recently bought a bunch of Michael Jackson's clothes - his actual clothes from his tours.

''The idea was to keep them for him. I actually don't really want to wear them; they're Michael's clothes.

''[But] there's a couple of pieces I have to the side and I have his sweaters that I put on - I wear that when we're mixing and finish up a record. I feel something from the clothing.''