Laura Prepon Returns on ‘How I Met Your Mother’

Tonight at 8:30pm EST, CBS’ How I Met Your Mother will welcome back That 70s Show alumna Laura Prepon, who’s reprising her role as Ted’s college ex-girlfriend Karen from the last new episode “Sorry, Bro.”

During “The Front Porch,” Ted gets into hot water with Karen when she discovers earrings that belong to someone else in his bed. It turns out Lily is behind the whole incident, and it’s not her first time deliberately interfering in one of Ted’s relationships. Bad, bad girl! And she looks so deceptively sweet and innocent.

Also up tonight on CBS’ two-hour comedy block are new episodes of The Big Bang Theory at 8pm (“The Work Song Nanocluster”), Two and a Half Men at 9pm (“My Son’s Enormous Head”), and Rules of Engagement at 9:30pm (“Jeff’s New Friend”), the last of which will feature a guest appearance by funnyman Orlando Jones (Men in Trees).

How I Met Your Mother airs Mondays on CBS at 8:30pm EST and Mondays at 7pm and 7:30pm on Lifetime.