Heidi Klum Dishes on Sofia Vergara's First Day on 'America's Got Talent': 'She Just Went For It!' (Exclusive)

The 'Modern Family' star fills the fourth seat on the panel for the show's upcoming 15th season.

Heidi Klum couldn't be happier to be back on America's Got Talent -- and work with Sofia Vergara!

ET's Lauren Zima caught up with the supermodel at the AGT season 15 kickoff at Pasadena Civic Auditorium on Wednesday, where she dished on working with the Modern Family star.

"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. 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."

Vergara joins Klum, as well as Simon Cowell and Howie Mandel, as judges for the next season. So what kind of judge will the Colombian actress be? Will she be as tough as Cowell?

"I'm excited to see what's gonna happen on that side of the desk," Klum said. "I'm now sitting next to Howie, and Howie is chatty. So it's gonna be very hard for me to focus, already I'm distracted very easily."

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Klum also confirmed that Vergara already gave an act a Golden Buzzer on the first day. "Sofia, can you believe this? First day, she just went for it. I was like, 'Kudos to you, Sofia Vergara,'" Klum shared. "She just went straight for it. She's not messing around. See for me, it's always, like, if I have a second thought then I just won't do it. If I have it in my gut, and I'm like, yes, I go straight for it."

As for how Klum is feeling about returning to the judges' seat, she admitted it "didn't take much convincing. I'm like, 'I'm back!'"

"I'm super excited that I was asked to come back. I mean, it's so amazing! America's Got Talent! It's definitely more fun being in the auditorium than watching it from at home," she expressed. "I just love sitting in that seat, I love having that power of the button." 

"I missed everyone here because it's just so much fun," she continued. "I do a lot of television. I have to say this is right up [there] because of the variety aspect. I love that. I also love that you never know who comes next, you know? It can be anyone."

ET also chatted with Vergara about joining the competition 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."

Hear more of what she shared in the video below.

America's Got Talent returns in May on NBC.