The flashbacks continue on "How I Met Your Mother," which returns for a fourth season. "How I Met Your Mother" airs Mondays at 8:30 p.m. ET/PT on CBS.

Gallery: Meet the cast

There's love all around on the fourth season premiere that has Stella -- guest star Sarah Chalke -- responding to Ted's (Josh Radnor) proposal, which producers say will get a definitive answer, no maybes. Barney (Neil Patrick Harris) meanwhile comes to the realization he loves Robin (Cobie Smulders). Oh, and let's not forget Regis Philbin, who will play himself in the Sept. 29 episode in which Marshall (Jason Segel) journeys to find the very first burger he ate in New York.

"How I Met Your Mother" airs Mondays at 8:30 p.m. ET/PT on CBS.