Jet Li's action adventure The Forbidden Kingdom has topped the US box office chart.

The Rob Minkoff-directed movie held off competition from Russell Brand and Kristen Bell's romantic comedy Forgetting Sarah Marshall, which landed at two.

Other new entries came from Al Pacino's crime thriller 88 Minutes in fourth spot and Nathan Frankowski's documentary Expelled: No Intelligence Allowed, which went straight in at number nine.

Last week's number one Prom Night slipped to third place.

The top ten in full:

1. (-) The Forbidden Kingdom - $20,870,000
2. (-) Forgetting Sarah Marshall - $17,347,600
3. (1) Prom Night - $9,100,000
4. (-) 88 Minutes - $6,800,000
5. (4) Nim's Island - $5,650,000
6. (3) 21 - $5,500,000
7. (2) Street Kings - $4,000,000
8. (6) Horton Hears A Who! - $3,500,000
9. (-) Expelled: No Intelligence Allowed - $3,152,896
10. (5) Leatherheads - $3,021,840