Criminal Minds: Evolution co-stars Liana Liberato and Zach Gilford were spotted together attending the People and InStyle’s Drive-By Party in Las Vegas on November 21, ahead of the annual Grand Prix.In the wake of their red-carpet appearance, an insider told Us Weekly in an exclusive interview on Tuesday that the duo is reportedly “dating,” but the relationship is “fairly new.”“They started dating after they worked together,” the source told the publication.They also added that Liana Liberato, 30, and Zach Gilford, 43, were “invited” to the Drive-By Party, and it’s the “first event they have been at together.”Liana Liberato was previously married to model and Instagram star Tommy O’Brien.As for Zach Gilford, he filed for divorce from his wife of 12 years, actress Kiele Sanchez, in April 2025. They share two children.Exploring Liana Liberato’s relationship with Tommy O’BrienAccording to Famous Birthdays, Liana Liberato began dating Tommy O’Brien in 2015. He wished her on Instagram on their first anniversary on October 25, 2016. Meanwhile, she wished him on his birthday via X in July 2017.The couple got engaged in July 2020. When and where they got married remains unknown. However, in November 2023, Liana’s fanpage @liberatosources shared two “throwback photos” of the pair’s “wedding of dreams.”The same account shared a fun picture of Liana Liberato and Tommy O’Brien in June 2024. However, neither the actress nor the Instagram star has mentioned the other on their social media profiles. O’Brien has over 22,500 followers on his @tommyobrien11 Instagram account, where he has only two posts at the time of writing. He launched his profile in May 2013.Later, Tommy rose to fame in November 2016 after appearing in the music video for Justin Bieber and DJ Snake’s collaborative song, "Let Me Love You," which garnered 20 million YouTube views in less than a week.Zach Gilford worked with his estranged wife on Criminal MindsZach Gilford crossed paths with Kiele Sanchez on the sets of the 2010 TV movie Matadors. A year later, in November, they got engaged. The now-estranged couple married in December 2012.Sanchez suffered a miscarriage in 2015. Later, she welcomed two children, Zepplin and Revel, in 2017 and 2020, respectively.The pair appeared together in the 2014 dystopian action-horror movie The Purge: Anarchy and later as an on-screen couple on Criminal Minds. Reflecting on their shared time, Zach Gilford told Us Weekly in August 2024 that filming was “harder” as the nature of their scenes was “pretty gross.”“Honestly, all those scenes are so f**ked up. I’ll only speak for myself. Kiele can obviously speak for herself, but it felt gross [bringing those darker moments to life together],” he added.Zach continued, “We’ve worked together several times and in very different situations. But there’s a theme on set when you are coworkers but also a married couple. It’s kind of trying to walk that tightrope.”Zach Gilford joined Criminal Minds: Evolution in 2022 as serial killer Elias Voit. Kiele played his wife, Sydney. Sanchez left the show in June 2024, during the 17th season. Liana Liberato made her debut on the same episode, “Kingdom of the Blind,” as Jade Waters.