Happy days are here again for Kristen Stewart!

The On the Road actress, 22, was perhaps the most-anticipated A-list guest at the Thurs. Sept. 27 Spring/Summer 2013 Balenciaga ready-to-wear show at Paris Fashion Week. Stewart, who's shot numerous ads for the high-end designer, turned up for the event decked out in floral jeans, black top, Balenciaga quilted yellow leather jacket and ankle boots.

PHOTOS: Kristen's grunge-to-glam evolution

The best accessory for the star, recovering from her July cheating scandal? An unmistakeable, ear-to-ear smile! In a contrast to Stewart's outing earlier this month at the Toronto Film Festival -- where Stewart seemed understandably tense for her first red carpet since the revealed fling with Rupert Sanders -- Stewart appeared relaxed and comfortable for the cameras.

PHOTOS: Kristen's affair

One major reason for that smile? Stewart has reconciled with Robert Pattinson -- and they've moved back in together, a source recently confirmed to Us Weekly.

Having cautiously forgiven Stewart for her July 17 fling with married Sanders, 41, Pattinson, 26, is "is extra-sensitive right now. He's insecure," the source says.

PHOTOS: Kristen, Rob and their daughter (!) in Breaking Dawn Part 2

The on-again pair will presumably be hitting the red carpets together when Breaking Dawn: Part 2  -- the fifth and final film in the Twilight saga -- hits theaters in November.

This article originally appeared on Usmagazine.com: Kristen Stewart Smiles, Stuns at Balenciaga Show in Paris