With The Twilight Saga: Breaking Dawn -- Part 2 premiering worldwide this week, Peter Facinelli** made a slightly quieter debut Nov. 15: A new girlfriend.

In NYC on Thursday night, Facinelli, 38, attended a screening of the franchise's hugely anticipated fifth installment at Landmark Sunshine theater, with an official afterparty at hotspot Finale.

His date for the evening? Actress Jaimie Alexander, who has costarred with Facinelli in episodes of Nurse Jackie as well as the film Loosies (Facinelli also wrote the screenplay). According to a witness, the stunning 28-year-old brunette hung back as Facinelli posed on the red carpet with costars Kellan Lutz** and Ashley Greene. (Their costars Kristen Stewart, Robert Pattinson** and Taylor Lautner** are promoting the film overseas.) When cameras weren't flashing, howeve, Facinelli and Alexander held hands and quietly stole kisses throughout the night.

"They have been very discreet of their relationship," a source recently told Us Weekly of the budding romance. Indeed, it's been eight months since Facinelli and Jennie Garth announced they were separating after 11 years of marriage.

He and the Beverly Hills, 90210 alum, 40, share daughters Luca, Lola, and Fiona. In the wake of the split, Garth has thrown herself into the dating game -- hanging out with HGTV's Antonio Ballatore, photographer Noah Abram and insurance exec Jason Clark.

Said Facinelli of Garth in April: "I love her, we're just going to have a different relationship. We're very dedicated to being great parents."

This article originally appeared on Usmagazine.com: Peter Facinelli Debuts New Girlfriend Jaimie Alexander at Breaking Dawn Part 2 Bash in NYC