Kevin Corrigan, Constance Zimmer, Giovanni Ribisi, Brooklyn Decker and Anthony Michael Hall have also signed on for the indie film, reports The Playlist.
According to a casting call, the film centres around a couple of personal trainers who take on a newly-wealthy but very out of shape client.
'Mumblecore' filmmaker Bujalski's previous films include Mutual Appreciation and 2013's Computer Chess.
Pearce can currently be seen with Robert Pattinson in The Rover.
Smulders will star in Avengers: Age of Ultron in 2015.
Results will begin shooting in July.