They've been a rumored couple since the beginning of August, and now George Clooney, 50, and former wrestler Stacy Keibler, 31, are taking things public.

The two stepped out on the red carpet Saturday night at the Toronto International Film Festival for the premiere of Clooney's The Ides Of March ... though they did not pose on the carpet together.

But, our sources tell us they jointly attended several parties after the premiere.

For her part, Stacy Tweeted on Sunday, "Loved my vintage @armani dress last night. Thinking about wearing @armani again tonight :) Having a blast at #TIFF". We would be too!

George broke up with ex Elisabetta Canalis at the end of June. It doesn't take long for him to rebound!