America's Got Talent returned Tuesday for its second night of live quarterfinals, and there was a new face at the judges' table. Kenan Thompson sat in for the injured Simon Cowell, and the longtime Saturday Night Live star brought his trademark warmth and charm to the show.

Thompson sat alongside Heidi Klum, Sofia Vergara and Howie Mandel, as 11 acts tried to win over the votes of viewers across America.

From singers like Kelvin Dukes, Kameron Ross, and the 14-year-old Daneliya Tuleshova, to dance groups like The Shape and BAD Salsa, Thompson had support and insightful critiques for all the acts.

The show saved the best for last with an emotional performance from Voices of Our City Choir -- the group that previously earned host Terry Crews' Golden Buzzer during the audition rounds.

The choir belted out a powerful rendition of "Stand by Me," which brought many viewers in the virtual audience -- who could be seen watching on a wall of screens behind the judges -- to tears.

"That was incredible," Thompson said after the performance. "I don't know if you get a kick out of making people cry their eyes out, but that's what you guys do every time you hit the stage... That was amazing, thank you."

Thompson's appearance this week follows Kelly Clarkson's guest appearance during the first night of the live rounds -- all a result of Cowell injuring his back earlier this month in a bike accident.

ET's Kevin Frazier spoke with Klum after Tuesday's show, and addressed the possibility of Cowell returning to the show for the semi-finals in a few weeks.

"Let's give him another minute," Klum said. "He's had about a half a minute. I mean it's been one week and he's already at home, I think that's absolutely incredible. So, you know, I would say let's give him another week and let's see how far he is then."

Mandel, meanwhile, said he missed Cowell being behind the judges' table, but added, "I know for sure she is watching the show."

Cowell underwent a six-hour surgery, which included having a metal rod placed in his back, after an electric bike accident at his Malibu, California, home. ET learned last Tuesday that the 60-year-old judge is walking again as part of his recuperation.

On Monday, ET also learned that Cowell was happily back home and doing well. For more on Cowell's recovery, watch below.

America's Got Talent airs Tuesdays and Wednesdays at 8 p.m. ET/PT on NBC.

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