The actors were spotted packing on the PDA at the Killing Them Softly afterparty at No. 8 in New York City Nov. 26. "They were sitting in a booth and he had his arm around her and they would kiss from time to time," a fellow attendee reveals. "They definitely tried to keep a low profile and left at separate times."
Prior to their courtship, Cannavale, 42, was married to actress/screenwriter Jenny Lumet from 1994 to 2003. The have one son, Jake, 17. After their divorce, he dated actresses Annabella Sciorra, Alison Pill and Sutton Foster. Bridesmaids star Byrne, meanwhile, previously dated writer/director/actor Brendan Cowell and writer/director Gregor Jordan.
Byrne, who played Ellen Parsons for five seasons on Damages, next appears in the movie The Place Beyond the Pines, costarring Ryan Gosling and Eva Mendes. Cannavale recently appeared on Showtime's Nurse Jackie and ABC's Modern Family.