Bradley Cooper, Kristen Bell in 'Hit & Run' trailer - watch
Bradley Cooper and Shepard's fiancé Kristen Bell also star in the road trip movie, to be released on August 24 in the US.
The Old Dogs comedian wrote the project, and co-directed with David Palmer.
Kristin Chenoweth (Glee), Michael Rosenbaum (Smallville), Beau Bridges (The Descendants), Tom Arnold (True Lies), and David Koechner (Anchorman) also star in the comedy.
The film centres on Charlie Bronson (Shepard), a former getaway driver who escapes Witness Protection to drive his girlfriend (Bell) to Los Angeles in order for her to get her dream job.
The pair are then followed by the authorities, Charlie's witness protection agents and his former gang colleagues on their long trip.
Hit & Run currently does not have a UK release date.
Kristen Bell and Dax Shepard recently stated that they will not marry until gay marriage is legalised.