Acclaimed playwright David Mamet fears his actress daughter Zosia will never find a man because she has a filthy mouth.

The Girls star, 25, portrays innocent Shoshanna Shapiro on the hit U.S. Tv series and she admits her father wishes she would sound a little more like her clean-living character in real life.

She tells the New York Post, "My father was... the one who told me I needed to clean up my mouth or I'd never find a man.

"What's very important to him is manners. Show up on time. Always send thank you letters. He is one of the more thoughtful humans I've ever met. He's a great man and a very good dad."