Inside ‘The Hills’ Revival: Audrina Patridge, Justin Bobby Brescia Filming Together

The Hills aren’t just alive, they’re ringing with the sounds of an Audrina Patridge and Justin Bobby Brescia reunion! Cast members of The Hills revival have officially started filming the new series, a source tells Us Weekly.

“They are friends,” the source explains, noting Patridge is “still hanging out” with her ex Ryan Cabrera. “They are not back together as of now.” (Patridge and Cabrera split in September, five months after rekindling their romance.)

Brescia, 36, and Patridge, 33, dated on and off throughout the original run of The Hills. Brody Jenner has also started filming the show with costars Frankie Delgado, Stephaine Pratt and Patridge, per the source. Newcomer Mischa Barton, however, has not filmed with any of her new costars yet.

The O.C. alum, 32, confirmed her casting on Wednesday, October 3. “Welcome to The Hills, bitch,” she said in an Instagram video to fans, referencing an iconic line from the teen drama, which was the driving force behind MTV’s Laguna Beach: The Real Orange County, which then inspired The Hills.

“The secret’s out… I’m joining the cast of The Hills,” Barton captioned the post. “When MTV approached me with the chance to be part of the reality show that was inspired by The OC, it felt like the perfect opportunity for an irresistibly inviting new chapter.”

An insider added that Barton’s appearance on The Hills: New Beginnings is “going to document her comeback.”

“Hopefully people will see her in a new light and not just because of personal problems in the years past,” the insider explained to Us earlier this month.

While Lauren Conrad, Kristin Cavallari and Lo Bosworth have decided not to be a part of the revival, Heidi Montag, Spencer Pratt, Jason Wahler and his wife, Ashley, and Whitney Port are all returning.