Have mercy!

During Sunday night’s All-Star duet episode ofAmerican Idol,Brett Youngand Laci Kaye Booth sang the country star’s song “Mercy,” and judgeKaty Perrywas quick to reveal her favorite contestant.

“I mean, from the moment you walk onstage, you sprinkle stardust everywhere,” Perry, 34, said. “I thought I was watching something on the Grammys. I was like, ‘Best new artist,’ I don’t know. I don’t want to play favorites but … but fill in the blank!”

Brett Young and Laci Kaye Booth.ABC/Eric McCandless

BRETT YOUNG, LACI KAYE BOOTH

“So the country girl got you,”Luke Bryanasked.

“It’s not about genre, it’s about feeling,” Perry added.

LUKE BRYAN, KATY PERRY, LIONEL RICHIE

In Sunday and Monday’s episodes, all-star musicians including Ben Harper,Julia Michaels, Shaggy, Lukas Graham, Chris Isaak, Cynthia Erivo, Jason Mraz, Pat Benatar & Neil Giraldo, Elle King and Lovely the Band will join forces with the remaining contestants to perform powerful duets.

“Tell me about this group so far,” Seacrest, 44, asked Bones. “What have you been focused on? What’s been getting your attention?”

“It’s such a diverse group of artists and it’s really them playing to their strengths inside their diversity,” said Bones, 38.

“What’s been the biggest challenge?” asked Seacrest.

“I think you have some great performers that are struggling with their stage presence,” Bones responded. “So it’s really trying to find what they’re strong at, and then get better on the other side of it. So, that’s what we’re working on.”

American Idolairs Sundays at 8 p.m. EST, with five additional Monday night episodes airing now.

source: people.com