The couple, along with the Hunger Games: Mockingjay actor’s mom Diana Ross, fêted the star at STK Downtown in New York on Tuesday night.
“They were excited and talking about Ashlee and Evan’s upcoming wedding,” a source says, adding that the groom-to-be was filming a movie next door to the restaurant. “Everyone was in great spirits.”
The group of 16 feasted on lobsters and filets while sipping on Macallan and Cokes.
Though his superstar mother left the festivities early, Simpson, 29, and Ross continued their evening of love and laughs.
“Evan and Ashlee were kissing each other non-stop all night,” the source adds.