Ben Stiller as Speedman and Robert Downey Jr. as Kirk Lazarus
The comedy - which features Stiller, Jack Black, Robert Downey Jr. and Tom Cruise - beat out new futuristic thriller, Babylon A.D. starring Vin Diesel - which grossed $9.7 million (GBP5.2million) in its first week of release, coming in second place.
The Dark Knight moved up a spot from last weekend (beg22Aug08), to number three, taking in an additional $8.75 million (GBP4.73million).
The Batman film now boasts total takings of $502.4 million (GBP271.6million) in its four weeks - becoming the second movie in Hollywood history to top $500 million (GBP270.3million) at the domestic box office.
Rounding out the top five is Anna Faris-starring comedy The House Bunny, coming in at number four with taking of $8.3 million (GBP4.5million).
Don Cheadle-starring drama Traitor follows, taking in $7.9 million (GBP4.3million) in its first week.
Source: WENN