Sara Gilbert has been added as a series regular on CBS’ “The Big Bang Theory.”

Gilbert guested on three segs in the Warner Bros. TV comedy’s frosh year. She’ll continue in the role of egghead Leslie Winkle, a love interest to Johnny Galecki’s Leonard, a fellow egghead who’s trying to come out of his shell with women. Gilbert and Galecki previously co-starred as sweethearts on the later seasons of ABC’s “Roseanne.”

In addition to the CBS sitcom, Gilbert has recently logged guest shots on NBC’s “ER” and ABC’s “Private Practice.”

“Big Bang,” co-created and exec produced by Chuck Lorre and Bill Prady, bows its second season Sept. 22.