Laura Prepon Engaged to Ben Foster

— -- Laura Prepon and Ben Foster are engaged, a source confirmed to ABC News.

The couple, first linked this past summer, made their red carpet debut last night at the New York premiere of "The Girl on the Train."

Prepon, who appears in "Orange Is the New Black," was sporting a ring on her left hand during the event.

This will be the first marriage for the actress, 36, and the actor, 35. Previously, Foster had been engaged to actress Robin Wright Penn, but they split last year.

Prepon is the second "Orange Is the New Black" actress to get engaged this week: Samira Wiley announced her engagement to writer Lauren Morelli yesterday.