"Every year [the models] do an acting challenge, and since I had been in Spamalot and was doing the Broadway thing, Tyra [Banks, the show's host] called and wanted me to be a part of it," Aiken, 30, tells PEOPLE.
"I did a scene with some of the girls and then later on tried to help judge that scene," he explains.
The aspiring models were all excited to meet the former American Idol singer. "It was kind of neat to be able to talk to some kids who were going through something similar to what I had been through so many years ago on Idol," he says, observing what he termed their "reality-show stress."
"I was on the other side of the table for once," he says, "which was a surreal experience for me."
'We Just Clicked'Clay was delighted to help, given he's such good friends with Tyra Banks, 35. "I love her to death," he says. "For some reason we just clicked when we first met, and we try to stay in touch and see each other whenever we're in town."
Of the supermodel mogul, Aiken says: "She's such a real person, and I think that's something people didn't know about her until her talk show. She doesn't try to be something she's not. She'll be as nerdy as she needs to be, or whatever she needs to be. I think that's why people are attracted to her, and I think that's why we became friends."