Following speculation that MTV would welcome new faces to the cast of the reality series revival, the 'O.C.' actress has been named its newest star.

The Hills and The O.C. are crossing over.

MTV announced on Wednesday that actress Mischa Barton has joined the cast of the Hills reboot. Barton will share the screen with original stars Heidi Montag, Spencer Pratt, Audrina Patridge, Jason Wahler, Frankie Delgado, Justin Bobby Brescia, Stephanie Pratt, Brody Jenner and Whitney Port.

Barton's casting comes after speculation that MTV had plans to welcome new faces to the cast of the beloved reality series. Barton rose to fame thanks to her lead role as Marissa Cooper on Fox's The O.C., which premiered in 2003. Incidentally, the teen drama served as inspiration for MTV's pioneering reality series Laguna Beach: The Real Orange County, which debuted in 2004, and ultimately became the launching pad for The Hills, which aired for six seasons from 2006 to 2010.

Though Barton has signed on to the reboot, titled The Hills: New Beginnings, she has previously said that she would "probably not" want to reunite with her O.C. castmates ever again.

"It's something I came so close to not doing," she told the U.K.'s Metro in 2014. "I had a really great thing with film. People say be grateful for what you have, but it [is] certainly not the kind of thing I was expecting it to be …I've kind of seen it all."

Aside from playing Cooper from 2003 until the character’s death in the 2006 season three finale, Barton is best known for her work as a child star in films including Notting Hill and The Sixth Sense — and making news off-camera.

Barton later publicly announced her casting on New Beginnings in a Wednesday evening Instagram post. She shared a video of herself listening to The Hills' theme song, "Unwritten" by Natasha Bedingfield, before saying, "Welcome to The Hills, bitch" — an obvious reference to The O.C.

In her accompanying caption, the star — who made her reality TV debut on 2016's season 22 of Dancing With the Stars — revealed why she decided to participate in the MTV reboot. "The secret’s out... I’m joining the cast of The Hills," she wrote. "When MTV approached me with the chance to be a part of the reality show that was inspired by The OC, it felt like the perfect opportunity for an irresistibly inviting new chapter."

The Hills: New Beginnings was announced in August at the 2018 MTV Video Music Awards — where several castmembers reunited on the red carpet at New York's Radio City Music Hall. The show will follow the cast, their significant others, children and friends living and working in Los Angeles. While Barton does not have documented relationships with any one of The Hills' original stars, Pratt and Montag recently started following her on social media.

As has been reported, Hills series lead Lauren Conrad and her eventual replacement, Kristin Cavallari — both of whom starred on Laguna Beach — will not be involved in New Beginnings. While Cavallari's E! docuseries, Very Cavallari, has likely prevented her from participating in the show, a source told The Hollywood Reporter that Conrad passed on the opportunity because she is focused on her clothing lines and lifestyle brand.

During a recent interview with THR, Conrad's former co-star Port shared details about the revival — and revealed that she's gently nudged the fashion designer to get in on the action.

"I get it. We're all at different points in our lives. Most of us have young families and everybody needs to protect their families in the way they feel is right," Port said of Conrad, who has a 14-month-old son, Liam, with husband William Tell. "I don't judge Lauren for not wanting to do it.

Added Port: "I have tried to convince Lauren through people. I haven't gotten directly to her, but I recently spoke to one of her friends and I was like, 'Tell her to do it!' Who knows? Maybe she'll say yes in the future. I feel like the door's always open."

Though The Hills was once known for its cinematic production and carefully crafted storylines, Port said that she anticipates a more authentic version of the show with New Beginnings. "There isn't a need to create storylines this time around, honestly. There's enough going on in our lives at the moment that they're not going to have to make anything up," she said. "What's cool about the reboot is it's going to be a slice-of-life type of show."

The Hills: New Beginnings starts filming this month and is expected to premiere on MTV in 2019.

Oct. 4, 6:27 a.m. Updated with Barton's Instagram confirmation.