According to NBC, the actors won't be playing themselves. However, they will be singing in their episodes.
Jonas will play Lyle West, a hot sitcom star who started his career as a child actor on Broadway. The show that gave him his start was written by Tom (Christian Borle) and directed by Derek (Jack Davenport).
Peters will play Leigh Conroy, Ivy's (Megan Hilty) mother. Peters' character is a Tony award-winning actress who is now living vicariously through her daughter.
Jonas will soon take on the lead role in 'How to Succeed in Business Without Really Trying' and Peters currently stars in 'Follies.'
'Smash' follows the creation of a musical based on Marilyn Monroe's life. Debra Messing, Anjelica Huston and Katharine McPhee headline the all-star cast.
'Smash' premieres Mon., Feb. 6, 10PM ET on NBC