Actor Oliver Platt arrives for the premiere of Year One in New York June 15, 2009. REUTERS/Stephen Chernin

Director Ed Zwick's Love and Other Drugs cast has swollen a bit further.

Gabriel Macht, Hank Azaria and Oliver Platt have signed on to the romantic comedy that Zwick is directing for Fox. They join Anne Hathaway, Jake Gyllenhaal, Judy Greer and Josh Gad.

The project is based on Jamie Reidy's nonfiction book Hard Sell: The Evolution of a Viagra Salesman. Filming is scheduled to begin later this month.

Macht plays a hotshot Prozac salesman who's involved romantically with Maggie (Hathaway), a free-spirited woman with Parkinson's disease who enters into a relationship with charming Viagra salesman Jamie (Gyllenhaal).

Azaria plays an unscrupulous doctor and client of Jamie's, and Platt plays his boss, a beleaguered pharmaceutical rep desperate to boost Jamie's sales.

Macht stars in the thriller Whiteout, which opened Friday. Azaria recently appeared in Night at the Museum: Battle of the Smithsonian and Year One, while Platt was also in Year One.