Kristen Stewart attends the Balenciaga Spring/Summer 2013 show as part of Paris Fashion Week on September 27, 2012. Credit: FameFlynet

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.

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.

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.

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.