For the first time ever, America's Got Talent was without a live audience in the audition rounds.
Tuesday's episode showed how the coronavirus pandemic affected production on the NBC series earlier this spring when judges Simon Cowell, Sofia Vergara and Howie Mandel were forced to continue filming in an empty venue in Pasadena, California.
"I felt a little pressure to make the contestants feel as though I was just as engaged as if there was an audience there and making them feel I was judging them on their performance and not the reaction of a crowd," the Modern Family alum, 48, tells PEOPLE.
"I think the act that had it the hardest was a group of at least 30 whose job was to pump up the crowd that wasn't there," Stonestreet recalls, referencing the Wildcats cheerleaders from Plano, Texas.
Though a live audience was eventually eliminated to follow safety guidelines, one contestant received a significant reaction when veteran judge Mandel, 64, pushed his Golden Buzzer.
"He was something that has never been seen on the stage of AGT, which is a tough thing to say," the comedian tells PEOPLE of his Golden Buzzer-winning act Brandon Leake from Stockton, California, who is the franchise's first-ever spoken word poet to compete. "It's not a category you're familiar with because he's not a singer, dancer, danger act. I was excited because I had never seen it before on our stage. It just blew me away, and that's kind of indicative of what this season was."
Mandel adds, "And then the pandemic hit! We got notice that we can keep going but let's go without an audience, which was so weird but incredibly doable because there have been auditions when we used to do our middle rounds where people came back and did it without an audience. It wasn't totally alien."
Calling the pandemic-affected production "the most different and most surreal experience," Mandel also recalls costar Klum getting sick. "Heidi started coughing beside me and she went home. We were so scared," he remembers. "As it turned out, luck will have it, it was not positive and she just had the flu, which is bad enough."
Another first, Mandel says, was a guest star making a cameo on such short notice. "They brought in Eric to fill in and we had never had a guest judge during an audition with no audience. It was all weird and new," he shares. "Every element and every step of the way has been so exciting and different."
Cowell, 60, previously told PEOPLE that to carry on with the season, precautions needed to be implemented due to the pandemic. "We started to realize that, for obvious reasons, the audience was getting smaller and smaller and smaller. We had this obligation to make sure that everyone got their fair share, and was auditioned well," Cowell said of the in-person auditions, adding that it was "really, really important to every single person who turned up."
Meanwhile, first-time judge Vergara told PEOPLE that she was a "little upset in the beginning" of her inaugural season after production was shut down due to stay-at-home guidelines.
"I felt like I was robbed of the opportunity to experience and learn the whole thing," Vergara said. "I only had two weeks of actually shooting in the actual venue with the contestants. And then, they had to take away the audience. So that was different for me. I was already getting used to the whole thing, and how it was supposed to be."
Since the auditions were filmed, all the judges, including Klum, and host Terry Crews resumed production and filmed the Judge Cut rounds. Each act was filmed in separate locations with minimal AGT staff and did not perform in front of a live audience. (Safety and health protocols that adhered to state and local requirements were set in place.)
America's Got Talent airs Tuesdays (8 p.m. ET) on NBC.