Brandi Glanville Accuses Ex-Husband Eddie Cibrian Of Having Affair With Piper Perabo While Filming 'The Cave'

Brandi Glanville has alleged that her ex-husband Eddie Cibrian had an affair with one of his former co-stars during their marriage.

The "Real Housewives of Beverly Hills" alum, who was married to Cibrian from 2001 to 2010, claimed that he cheated on her with Piper Perabo while the two were filming their 2005 movie "The Cave."

"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," the 50-year-old reality star told Page Six. "And [Perabo] was a horrible c—t to me."

The "Unfiltered" podcast host said she became uncomfortable with Perabo and Cibrian's alleged interactions and claimed that the actress flirted with Cibrian in front of her despite knowing he was married.

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

Glanville said she became friends with some crew members, and they allegedly kept her clued in on her then-husband and his co-star's actions on set.

Glanville alleged that she heard "a lot of things" from the crew members, including "that Piper and Eddie were f—king."

After he wrapped up filming, the reality star said she confronted Cibrian about the alleged affair when he returned home to Los Angeles and threatened to leave him. But Cibrian denied the allegations.

"He convinced me that it wasn't true," Glanville recalled. "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."

Cibrian also allegedly brushed off her concerns, reportedly telling her that she was "just crazy," "jealous" and "that whole deal." She eventually chose to stay with him.

"And I was like, 'All right.' I was in love," she said of her choice to stick by Cibrian's side. "Like, I was blindly in love with the man."

But Cibrian denied Glanville's allegations that he cheated on her with the "Yellowstone" star during their marriage.

"I'm sad I have to address this, I really believed that we had come a long way, but this was untrue 19 years ago and it's untrue now. Just because someone thinks something might be true does not make it true. This is all so unnecessary," he said in a statement to Page Six Tuesday.

Perabo's rep did not immediately respond to the outlet's request for comment.

After eight years of marriage, Cibrian and Glanville announced their split in 2009 after he had an affair with his now-wife, LeAnn Rimes, whom he married in 2011.

Cibrian and Rimes met on the set of "Northern Lights" in 2008. The singer was married to Dean Sheremet at the time.

Glanville claimed she noticed that Cibrian and Rimes "were attracted to each other" when she visited the set. However, she found out about their affair in the press.

"Then one day, I ran to the grocery store and pictures of Eddie and LeAnn making out in a restaurant were plastered across the magazine Us Weekly," Glanville wrote in an op-ed for The Sun.

She continued, "I went online on my phone — and it was everywhere. There was video footage of them kissing over the table. It was devastating. I went straight home, passed out in my closet, cried and cried. He tried to convince me it wasn't real, but I knew it was over."