American Idol celebrated 20 years on Monday night (May 2), and the show offered up a series of performances from stars past and present, including Caleb Lee Hutchinson and Maddie Poppe.

Idol has whittled down its cast of contenders to its Top 7, which means fans are one step closer to finding out who will be named the Season 20 winner, and the competition is getting even more fierce. But, Monday night’s episode of the popular TV sing-off series saw the remaining finalists sitting out and taking a break from fighting for America's votes.

Instead, the latest edition, titled The Great Idol Reunion, put the pressure on former Idol contestants, calling on them to perform in celebration of the show's 20-year run.

Real-life couple Hutchinson and Poppe were two of those Idol alums invited back to the set. They made their return, showcasing their undeniable onstage chemistry with a powerful duet on “Islands in the Stream,” which the Bee Gees wrote and Kenny Rogers and Dolly Parton turned into a mega-hit.

With Hutchinson taking on the role of the late Rogers, and Poppe channeling Parton’s part of the ballad, the pair’s performance made for a memorable tribute to two of country music’s greatest legends. Hutchinson, who sported a denim jacket, dug into his lower register on the lyrics, while a formerly-blonde Poppe, dressed in a floral dress and sporting dark hair, flaunted her vocal talent by switching keys midway through the song.

“It’s good to see you guys together up there again!” Luke Bryan said afterward. “It’s like, ‘Oh my god! Five years ago. And, Maddie, obviously, you and Katy are channeling the same hair.”

Hutchinson and Poppe started their journey on American Idol by auditioning for its sixteenth season. Poppe ended up claiming victory, taking home the crowning win. Hutchinson didn’t go out without a triumph of his own, though. He took second place and even revealed he and Poppe were in a romantic relationship during the live finale of their season.

Since coming off of Idol, both artists have gone on to launch successful careers of their own. Poppe, who on the show plugged her latest track “The One That Got Away,” before sharing that she is going in a “whole new direction" with her music, has released a debut album entitled Whirlwind, and a holiday collection called Christmas From Home. Hutchinson, meanwhile, recently released his EP, Slot Machine Syndrome, produced by Brent Cobb.

Along with Hutchinson and Poppe, the 1-hour pre-recorded special also featured duets by Ruben Studdard and Jordin Sparks, Lauren Alaina and Scotty McCreery, Willie Spence and Grace Kinstler and Kris Allen and David Cook.

Original judges Paula Abdul and Randy Jackson also made an appearance on the show.

American Idol airs Sundays and Mondays on ABC.

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