Deschanel doubts acting ability

Zooey Deschanel worries she doesn't know how to act.

The 'Yes Man' actress - who has starred in 'The Good Life', 'The Happening' and 'Surf's Up' - feels like a new and inexperienced actress every time she starts work on a new movie and struggles to gauge how well she has done.

She said: "That's part of what makes acting so scary for me because like there will be total moments where I will be like, 'I have no idea what I am doing.' Acting is not a quantifiable thing. You cannot put a number on it.

You cannot be like, 'OK I have done my 10 hours and my work is done.'"

Although the 29-year-old beauty has just starred in Joseph Gordon-Levitt 's '500 Days of Summer', Deschanel doesn't enjoy watching "flimsy" romantic comedies and prefers movies which cater more specifically to her sense of humour.

She said: "I'm a fan of the screwball comedy genre, which I think is the forefather of romantic comedy. Actually I find so many romantic comedies today so flimsy, like a lot of talking, cardboard cut-outs trying to be funny.

"I like actors who don't try too hard to be funny like my favourite comedians Bill Murray and Steve Martin. I think they play the reality of the character and then the comedy comes out of that."