Zooey Deschanel is too scared to babysit her nephew.

The '(500) Days of Summer' actress' older sister Emily has a three-month-old son and although Zooey finds the tot "terribly cute" she doesn't like being left responsible for him unless there is someone else around.

Asked if she ever babysits, she said: "If somebody else is around. I don't ... I've never really babysat. I'm not great at babysitting. I kind of, like, don't know what to do, maybe if my mom was around or something. I like holding him, he really is terribly cute."

Despite her aversion to babysitting duties, Zooey - who split from her husband, Death Cab For Cutie frontman Ben Gibbard, in November - explained she is "pretty much always cheerful".

Zooey added: "I am pretty much always cheerful. Even early in the morning, I go on tour with my band and it's, like, 12 people on one bus. And I feel like I'm the one who's happy in the morning."