Foster made the Top 10 after performing Randy Travis’ 1987 hit “I Told You So”

Carrie Underwood is gushing over American Idol’s John Foster!

Speaking with PEOPLE in a roundtable interview after the live show on Monday, April 28, the “Before He Cheats” singer revealed why she has a soft spot for the contestant.

“He’s so sweet and fresh faced and he’s one of those people that I feel like… don’t even really know how good you are kind of thing,” Underwood, 42, says.

“Week to week, we have watched him progress so much,” she adds. “We were talking after his performance, me, Luke [Bryan] and [Lionel Richie] and we were just saying he’s probably the one that has grown the most since he’s been here.”

Carrie Underwood and John Foster.Disney/Eric McCandless (2)

Underwood believes that the Idol audience “loves him” — and there’s “so many reasons to want to root for him.” But for the “Jesus Take the Wheel” singer, there’s a personal connection.

“I feel like he kind of reminds me of my oldest son,” says Underwood, who shares two boys, Isaiah, 10, and Jacob, 6, with husband Mike Fisher. “When he’s over there singing to me, I kind of feel like a proud mom. He’s very good.”

On Monday night, Foster, 18, sang Randy Travis’ 1987 hit “I Told You So,” which Underwood covered for her 2007 album Carnival Ride. Toward the end of his performance, Foster approached the judges table and sang to Underwood directly.

Lionel Richie, Carrie Underwood and Luke Bryan.Eric McCandless/Disney via Getty

Reflecting on that moment, Foster says she’s “the reason” he chose the song — and he knew he needed to sing it to her.

“The fact that she was sitting there on the panel… the pressure was on. She has such a great version of the song but I knew that I had to sing to her and I knew that I had to let America know my passion for the song and music by connecting with her,” he says.

In addition to Foster, Josh King, Jamal Roberts, Mattie Pruitt, Thunderstorm Artis, Slater Nalley, Gabby Samone, Canaan James Hill, Kolbi Jordan and Breanna Nix are in the Top 10.

On April 20, Foster moved Idol viewers when he sang an original song, “Tell That Angel I Love Her,” which he wrote about a friend who died suddenly in 2022.

“You’ve kind of been a wildcard for me the whole time, but what you just did there removed all doubts in my mind that you deserve to be here,” said the “Kick the Dust Up” singer.

“When you open your mouth on this song, you’re country, but you’re also storytelling country,” Richie added. “Now whether that’s old, new, happening now, later, whatever the case may be, it was so believable and I heard every word of every part of your story and that’s what great music is about.”

American Idol airs Sundays and Mondays at 8 p.m. ET on ABC.