Former "Real Housewives of Beverly Hills" star Brandi Glanville went after Piper Perabo for having an alleged affair with her ex-husband, Eddie Cibrian.

In a new interview, Glanville accused the two of having a sexual relationship while filming "The Cave" in 2005.

"They did a movie together, and [my son] Mason was 1 year old and I went to the set, and it was in another country, Romania, I think," she told Page Six. "And [Perabo] was a horrible c--t to me."

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The reality TV star said that while she was on set to visit Cibrian, Perabo flirted with her husband.

"She was flirting with Eddie, like, right in front of me," Glanville further claimed in the interview. "I was like, ‘Am I here? Am I the only person [seeing this]? Like, what is happening?’"

"I made friends on set and I heard a lot of things," she explained, adding that crew members informed her "that Piper and Eddie were f---ing."

Glanville said she confronted Cibrian, but he denied anything happened.

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"He convinced me that it wasn’t true," she told the outlet. "We had a 1-year-old son, and he was the love of my life at the time and, you know, there was a lot of convincing me of things."

Representatives for Cibrian and Perabo did not immediately respond to Fox News Digital's requests for comment.

Cibrian also allegedly had affairs with Scheana Shay from "Vanderpump Rules" and LeAnn Rimes. The actor's relationship with the country music star led Glanville and Cibrian to call it quits for good.

Cibrian went on to marry Rimes in 2011.

Cibrian and Glanville met at a club in the 1990s, according to multiple reports. The couple was married from 2001 until 2010. They welcomed their first son in 2003 and their second in 2007.