Jennifer Lawrence shakes ''like a Chihuahua'' during interviews.

The 21-year-old 'Hunger Games' star admits she gets so nervous on the red carpet that by the time she gets to the interviews, she doesn't know what to do with herself.

She said: ''Out of the four premieres, I've tripped in two or three of them. Like, massive trips.

''It's so scary and then I end up getting so nervous that I get really hyper. So then I go do interviews and I'm like, 'I'm like a Chihuahua. I'm shaking. I'm peeing!' And then afterwards I'm like, 'I just talked about peeing on the red carpet!'''

Despite having been cast as heroine Katniss Evergreen in the film adaptation of Suzanne Collins' book trilogy, Jennifer still doesn't believe she was the right woman for the job.

Appearing on 'The Late Show With David Letterman', she said: ''I am a troll. I hate myself. I think the movie is great, but their biggest mistake was [casting] me.''

And the Oscar-nominated actress insists her decision to sign up for the film had nothing to do with its anticipated success.

She explained: ''I've never really paid attention to the box office or how much money any film makes before. This one, people keep reminding me, so now it's there, but it's not something I normally care about.''