Ashlee Simpson was “touchy feely” with fiancé Evan Ross at her ex-boyfriend’s birthday party.

The 29-year-old star became engaged to The Hunger Game actor in January and apparently both of them are on good terms with former lovers.

Ashlee and Evan attended her ex-beau Ryan Cabrera’s 32nd birthday bash last Sunday, which was held at the Kia Motors Malibu Estate.

“They were both super cute with one another, very affectionate and very touchy feely,” a source told Us Weekly of the future spouses’ behaviour at the party. “At one point Ashlee even had Evan sitting on her lap as they conversed with their friends.”

Ashlee dated musician Ryan in 2004 and he was once managed by her father, Joe Simpson.

She and Evan, who is the son of music legend Diana Ross, have hung out with Ryan together before, and it’s claimed Ashlee encourages everyone to get along.

“[She was] urging Ryan to play his new record for Evan so he could listen to it and maybe give him some insight on some lyrics that Ryan was struggling with,” the insider recalled.

“Evan and Ryan talked about collaborating and getting in the studio together. Both of them sounded super stoked on the idea and will be making it happen sooner than later.”

Ashlee and Evan are said to be tying the knot closer to the end of summer, on August 31. Soul singer Diana is supposedly performing at the nuptial ceremony.

The outlet reports several huge stars have been invited to the affair, including Smokey Robinson and Stevie Wonder amongst others.

Evan popped the question six months after he and Ashlee began dating.