Sara Gilbert joins 'Big Bang' as series regular

Will work with 'Roseanne' co-star Galecki again

The "Roseanne" reunion on CBS' "The Big Bang Theory" is becoming permanent.

Sara Gilbert, who did a three-episode guest stint last season, has joined the Warner Bros. TV-produced series as a regular.

She will reprise her role as Leonard's (Johnny Galecki) brilliant colleague and on-and-off love interest Leslie Winkle.

This mirrors the storyline of Gilbert and Galecki's characters on "Roseanne," Darlene Connor and David Healy, who also had an on-again, off-again relationship until tying the knot in the penultimate season.

Gilbert's role on the long-running ABC sitcom earned her two Emmy nominations.

She is repped by the Gersh Agency and Framework Entertainment.