Movies
Rex Features
It knocks Christopher Nolan's The Dark Knight into second place, while action thriller Taken falls to third.
Elsewhere, Tina Fey's Baby Mama debuts at five.
The top ten in full:
1. (-) Tropic Thunder - $3,051,215
2. (1) The Dark Knight - $1,340,174
3. (2) Taken - $1,155,263
4. (3) Mamma Mia! - $1,111,479
5. (-) Baby Mama - $770,317
6. (4) Star Wars: The Clone Wars - $693,175
7 (7) The Strangers - $429,359
8. (5) Pineapple Express - $424,418
9. (6) Wanted - $360,790
10. (8) The Bank Job - $344,979
Movie Reviews
'The Vow' reviewChanning Tatum tries to win back Rachel McAdams in romantic drama The Vow.
At the Movies
This Week's 5 Hottest Movie VideosTrailers for The Avengers and Spider-Man are among this week's highlights in film.
Movies Interviews
Daniel Radcliffe talks 'Woman in Black'The actor talks to Digital Spy about his first post-Potter outing.
Box Office Charts
'Chronicle' leads UK box officeSuperhero drama Chronicle leads the UK box office ahead of Journey 2.
