Sarah Silverman watches Michael Sheen's sex scenes ''all the time''.

The 43-year-old comic is a fan of her boyfriend's TV show 'Masters of Sex' and doesn't mind seeing him get close to his co-stars on screen.

She said: ''I watch him have sex on TV all the time.''

Sarah has a guest role on the next series of the show, but insists she has no plans to be on set if he's shooting sex scenes.

She added to the New York Post newspaper: ''No, I'd never go to set when that ... I don't want to know. It's so not sexy.''

Sarah can next be seen in 'A Million Ways To Die in the West' and though the role of local whore Ruth was written specifically for her by Seth Macfarlane, it was still a struggle to convince producers to agree to her casting.

She said: ''It was still hard to get the part. Suits would rather have a starlet than a 43-year-old Jew comedian.''

And the brunette star was thrilled to be cast in the movie because it appealed to her sense of humour.

She explained: ''I like doodie jokes. This is a combination of smart observational humour and aggressive stupidity.''