The 63-year-old Peters, a two-time Tony winner, will take on the role of Leigh Conroy, the Tony-winning stage mom of another regular character Ivy (Megan Hilty), and Jonas will play Lyle West, a sitcom star who began his acting career as a child on Broadway.
The drama was originally developed for Showtime. In August, NBC Entertainment Chairman Robert Greenblatt said Smash "may be the most adventurous show that we do, and it ultimately may be the most narrow show we do. It's hard to know where we're going to come out on the continuum there."
Smash, scheduled to premiere Feb 6, will air Mondays at 10/9c on NBC.