The twosome recently went public with their relationship, spotted walking hand in hand in New York City the weekend of July 15 and later laughing together over lunch.
“Their chemistry is undeniable — it’s why they’ve got a hit show on their hands,” shares a source. “There was a spark the moment they started running lines.”
Things heated up quickly between the pair, who have known each other “for the better part of a decade” due to Billy’s friendship with Naomi’s former love Liev Schreiber.
“But there are no hard feelings.When Liev found out, he wasn’t that surprised. They always got on so well together.”
“Splitting from Liev was devastating for Naomi, and she just couldn’t see herself with anyone else,” the source says. “Then this fell into her lap, and she couldn’t be happier.”