Sara Gilbert Returns with a Big Bang

Off camera, Sara Gilbert - aka Roseanne's most sarcastic teenager - is all grown up and a happy new mom with partner Allison Adler.

On camera, she's not only a recurring presence on ER, but she's also about to reunite with her former "husband," fellow Roseanne alum Johnny Galecki.

The Big Bang Theory, a new CBS sitcom, centers around Galecki and Jim Parsons (Judging Amy) as two socially awkward scientists who become friends with their hot new neighbor, played by Kaley Cuoco (8 Simple Rules).

Gilbert will guest star in a multiple-episode arc on the fledgling comedy as a physicist colleague and possible love interest for Galecki.

Provided the show survives the usual harsh new series cancellation rate, the chemistry's already built in.