Shannen Doherty admits she may have hit below the belt.
The Beverly Hills, 90210 alum confessed that she and costar Jennie Garth got into a blowout fight over an on-set prank.
"She was doing, she was calling it 'Pants-Down Day,'" Shannen explained on a March 3 episode of her podcast Let's Be Clear, "where she would pull the pants on some of the crew members in a funny way."
But when some of the crew got "pretty annoyed" with the joke, the Charmed actress decided to turn the tables on Jennie.
"I said, 'Skirt-Up Day,'" Shannen recalled to her guest, fellow show alum Brian Austin Green. "She always wore the men's Calvin Klein boxer shorts under her clothes, so I didn't think it was that big of a deal."
The move didn't go over too well with the What I Like About You actress, however. As Shannen remembered, Jennie "lost it" over the prank, leading to a physical confrontation their costars Brian and Ian Ziering had to intervene in and de-escalate.
Brian noted on the March 3 podcast, "It was a huge moment for everyone."
And that's not the only time the girls of 90210—which ran for 10 seasons starting in 1990—had bad blood. In fact, Shannen confessed to there being tension between her, Jennie and Tori Spelling through much of the show's filming—a stark difference from Brian, Ian, Jason Priestley and the late Luke Perry's relationship.
"It was always awesome to me that the boys got along so well," the 52-year-old reflected. "You guys were always very supportive of each other and congratulating each other, and it wasn't necessarily the same with the girls."
And Brian seconded Shannen's perspective on the on-set dynamics.
"I remember it got really rough and competitive for you all," he agreed. "That was not an easy situation to watch."
E! News reached out to Jennie's rep for comment but has not heard back.
Keep reading to revisit more famous celebrity feuds that have gone down over the years.