ET has learned that the Modern Family star is taking the model's seat as a guest judge at Wednesday's taping of the competition show, after Klum went home with the common cold the day before.
Stonestreet joins his Modern Family co-star, Sofia Vergara, who recently became a new judge for season 15 of AGT, Simon Cowell, Howie Mandel and host Terry Crews.
ET caught up with the AGT judges last week at the show's kickoff, where Vergara opened up about joining the NBC show. "I never, in my life, expected to do something like this," Vergara confessed. "It seemed like the right thing to do after 11 years of Modern Family to mix it up."
Heidi also dished on Vergara's first day, saying, "It's been amazing! We've only filmed one day so far and on the first day, she was like, 'I'm really nervous. I don't wanna do anything wrong,'" Klum recalled.
"And I said to her, 'You cannot do anything wrong. You just speak your truth. You just say what you just saw, if you like it and if you don't, and if you just elaborate on that, that's it,'" she said. "The nice thing is you don't have to memorize any text. You know, because on Modern Family, I'm sure she has to do pages and pages of memorizing. We don't have to memorize anything. We have no ear [piece]. There's no one talking to us in our ear. You see it and you speak what you thought of it."
Hear more in the video below.