Jennie Garth, Tori Spelling Throw Shade At Former 90210 Co-Star Tiffani Thiessen

Sounds like some Beverly Hills, 90210 (1990-2000) stars hold a grudge.

While serving as guest judges on RuPaul's Drag Race (2009-), Jennie Garth and Tori Spelling called out their former co-star Tiffani Thiessen. According to Entertainment Tonight, following a parody of the hit '90s show, Garth criticized contestant Aja, who had taken on the role of Thiessen's former character, Valerie. But Garth reportedly refused to utter Thiessen's name, instead opting to refer to the actress as something else altogether.

"As Ti... how do you say it?" Garth, 45, stopped to ask Spelling.

"Just say, 'That which we don't speak of,'" Spelling, 43, coached.

Laughing, Garth informed Aja, "Yes, we know her as 'That which we don't speak of.'"

Thiessen, 43, previously opened up about her relationship with her former co-stars during a 2012 interview with Howard Stern on his Sirius XM show (via Us Weekly).

"The girls were not very nice to me," she explained, regarding her start on the show. However, after some time, Thiessen said that Garth apologized to her and that the two became good friends. But, as with all good things, their friendship didn't last.

"We had a falling out and we grew apart," she told Stern. "I was the one who was hurt, let's just say that. I was the one who was hurt."

Thiessen also revealed that she'd once been close with Spelling as well—but that all ended after Spelling divorced her first husband, Charlie Shanian. "It was a hard situation for everybody," Thiessen said. "We were close with Charlie ... my best friend was Charlie's roommate. It was hard."

It's too bad the actors couldn't stay friends. But, judging from what Garth and Spelling said on RuPaul's Drag Race, the two sound like mean girls, so maybe Thiessen was better off cutting ties.