On Sunday, May 18, American Idol viewers will crown either John Foster, Breanna Nix, or Jamal Roberts as the show’s newest champion. At the semi-finals, judge and past Idol champion Carrie Underwood, who former judge Simon Cowell predicted would win Season 4, made a bold prediction of her own.

Carrie Underwood, Ryan Seacrest — 'American Idol'

“I remember your audition coming in and I felt like I had this diamond in the rough standing right in front of me,” Underwood told Foster after he performed his second song (“The Rainbow Connection”) in the semi-finals.

Underwood playfully added that she had to do some convincing with her fellow judges, Luke Bryan and Lionel Richie, to move Foster through to Hollywood. “I love that you’re standing here right now, proving me right,” Underwood added. “And I’m going to tell you right now, if you ain’t real careful, you might just win this whole thing.”

TV Insider asked Underwood after the semi-finals broadcast if Cowell’s prediction has stayed with her over the years — especially as it turned out to be correct! “It was much earlier in the competition when he said that to me,” Underwood said. “But, yeah, I mean, to have [Simon] make a bold prediction like that? It was like, ‘Oh. This could be possible.’”

American Idol: Does Ryan Seacrest Give Carrie Underwood Special Treatment? (I Think She Could Be His Favorite Judge Of All Time)

“I’m sure she plays that in the back of her head,” host Ryan Seacrest shared. “She was told by Simon, ‘You’re going to be the winner.’ I wonder if she’s got the same predictability factor?”

Underwood’s prediction for Foster may not have been early on the competition like Cowell’s was, but he still had to get through the semi-finals after she shared her belief. “I was thinking he has a really good chance of winning and I was right because now, he’s in the Top 3,” she says.

Underwood is the only current judge who has gone through the Idol process, so she knows what the finalists are probably thinking and feeling in this week leading up to the finale.

“They’re going to be in their hometowns, dealing with every person in the world that they’ve ever met,” she says. “They’re going to be there with a lot of people that they don’t know, too, all the while thinking about what they’re going to perform for the finale. There are group numbers and people showing up. There’s all that stuff to deal with along with the nerves and the stress.”

How can the finalists block out all the extraneous matters and focus on their performances? “I don’t know that you do,” Underwood shrugs. “This is kind of a taste of what the rest of their careers are going to be like. We call [American Idol] ‘Star Boot Camp’ because you learn a lot really fast. You learn how to sing live on TV, how to work with the cameras, how to appeal to the audience, how to deal with criticism, how to do press. You learn all this in a short amount of time, so you just do your best.”

Underwood speculating on a particular singer winning or not is fair game given her role as an Idol judge. Seacrest, however, isn’t put in the position of critiquing the crooners. “I think they’re all my favorites,” he says. “I stand next to them. I truly love them all.”

Seacrest, however, is calling out one winner for this season: Underwood, herself! “She really did a masterful job guiding the contestants and being the advocate that she needed to be for them,” he raves.

American Idol' spoiler: Watch Ryan Seacrest and Carrie Underwood hand out surprise platinum ticket on New Year's Eve

As the person who reads the name of show’s winning singer, Seacrest is privy to the identity of that individual for a few brief seconds (though it sometimes seems longer!) before everyone else learns it.

“I’ve done this 20-something times,” he says, “but I will tell you that every time we get to that last moment, I look down and when I actually see the winner, I feel the emotion before I say [the name]. And that will happen again on Sunday.”