The as-yet-untitled film tweaks the traditional buddy-cop formula, centering on a tighty-wound FBI agent (Bullock) who has to collaborate with a sloppy Boston cop (McCarthy) in order to bust a Russian gangster.
Feig is directing from a script by "Parks and Recreation" writer Katie Dippold, according to Variety, who broke the story.
McCarthy is part of the big ensemble cast of Apatow's upcoming "This is Forty," and will soon be seen opposite Jason Bateman in the comedy "Identity Thief."
On the TV side, she'll continue her Emmy-winning role on "MIke and Molly" this fall, and also recently signed on to exec produce a new CBS pilot.
Bullock recently co-starred with Tom Hanks in the Best Picture nominee "Extremely Loud and Incredibly Close." Alfonso Cuaron's highly-anticipated SF drama "Gravity," starring Bullock and George Clooney, was recently pushed back to 2013.
Also, for those keeping score, Bullock previously played an FBI agent in the two "Miss Congeniality" films.
Feig is currently working on a remake of the French comedy "The Intouchables," so this new film will likely shoot after "Intouchables" wraps.