Glee's Chris Colfer doesn't want to say which star he'd like to work with next -- because the last time he was asked, he answered, "Bea Arthur" ... and then she died.

"Somebody asked me if there was anyone in the world I could pick to play my grandmother ... so I said I'd love to work with [Bea Arthur], and then she passed away the next week," Colfer told Conan O'Brien on The Tonight Show Tuesday night.

The two also joked about Colfer's high-pitched voice ("When I was growing up, everyone would always think I was my mother on the phone") and his high-school experience.

"I was president of the writing club," he joked. "I was the president and the only member ... for four long years ... I remember the rallies where we'd have to recruit people and we'd be standing there in front of the entire school. I might as well have been selling houses on the Gaza strip."

Watch the video here and read Colfer's interview with The Advocate.