The star, who plays Bella Swan in the popular vampire franchise, is desperate to start production on Breaking Dawn, the last in the series.
She said: 'I can't wait to do it, I can't wait to get it out... it's the craziest, longest buildup.
'It's just like, Let's f***ing do it already, you know what I mean?'
Kristen, 20, told a US magazine: 'But at the same time, it's sad.
'Not to be totally and completely candid, but - I know some people think they're bad - but they'd be really bad if the cast didn't really love them.'
Breaking Dawn is due to start filming next month.
It is set for release in November 2011.
Eclipse, the last Twilight film to be released, hit screens in June of this year.