Peter Facinelli and Jaimie Alexander attend the 19th Annual Screen Actors Guild Awards on January 27, 2013. Credit: John Sciulli/

As guests of the Weinstein Company's SAG Awards 2013 after-party at Sunset Tower in Hollywood,Peter Facinelli and new girlfriend Jaimie Alexander were literally surrounded by Hollywood's best and brightest: Jennifer Lawrence, Sofia Vergara, Julianne Moore, Amanda Seyfried, Damien Lewis and Robert De Niro, to name just a few. But according to an onlooker, the twosome only had eyes for each other at the Fiji Water-sponsored bash.

Arriving at the party together, around 9pm, Facinelli, 38, appeared "totally smitten" with his Nurse Jackie costar, 28, an observer says. And who could blame him? In one of her first major red carpets, Alexander looked flawlessly in a black Marc Bouwer gown with a plunging neckline, an open back, and curve-flattering ruching.

Later on during the party, a tux-clad Facinelli hit the dance floor with his lady to bop along to Notorious B.I.G.'s "Hypnotize," stealing kisses as well. They were also spotted hanging outside on the patio -- staying warm by standing beneath heat lamps and kissing.

Facinelli, who split from wife Jennie Garth last March, quietly debuted his romance with Alexander at a Nov. 15 screening of The Twilight Saga: Breaking Dawn Part 2. "Peter's a classy guy who cares a lot about the people [around him] and...he makes me laugh," Alexander gushed to Us of her beau. "That's really more than I've ever found with anyone else."