American Idol Alums Chayce Beckham, Phillip Phillips and Alejandro Aranda Return for Top 20

Some of your favorite American Idol alums are back!

In honor of Sunday's Top 20 episode in the competition series, PEOPLE can exclusively reveal that three alums will be returning for special performances.

During the show, fans will see performances by Phillip Phillips, Alejandro Aranda (aka Scarypoolparty) and last season's winner Chayce Beckham.

In the exclusive promo video, out everywhere on Wednesday, judges Luke Bryan, Katy Perry and Lionel Richie set the tone for the nail-biting night where the top 20 contestants will be revealed.

RELATED: American Idol Frontrunner Kenedi Anderson Drops Out of Competition for 'Personal Reasons'

Mickey Bernal/FilmMagic/Getty; Alison Buck/Getty; Chayce Beckham/Instagram Phillip Phillips, Alejandro Aranda and Chayce Beckham

The video opens with Bryan, 45, saying, "Your journey is just getting started" before the performers are introduced, and the narrator teases that four contestants will be let go as Richie, 72, says, "You will not make it to the next round."

Once the 20 are revealed on Sunday, they will each perform before the judges and viewers at home will vote once again to determine who will make it to the next round.

Then, viewers learn that the top 14 will be announced during the live show on Monday, as Perry, 37, says, "We see your future on American Idol."

Meanwhile, Kenedi Anderson, this season's frontrunner announced on Instagram on Monday night that she would no longer continue on the competition series, after her pre-taped Top 24 performance aired.

"For personal reasons, I'm unable to continue on American Idol. This has been one of the hardest decisions I've ever had to make, but I know it's necessary," Anderson wrote. "I'm so grateful to American Idol, the judges, the producers, the amazing contestants, and all the fans who have supported me."

RELATED: Katy Perry Recovers from Hilarious Wardrobe Malfunction During Impromptu American Idol Performance

Randy Holmes/ABC/Getty Luke Bryan, Katy Perry and Lionel Richie

"Thank you for giving me such an amazing opportunity to share my voice, chase my dreams, feel so much joy and happiness doing what I love, and make lifelong friends along the way," she concluded.

"We are disappointed to see Kenedi leave, but we are excited to watch this celebratory 20th season unfold with the incredible talent vying to be the next American Idol," producer Fremantle Media told PEOPLE in a statement.

The show, hosted by Ryan Seacrest, will air live on Sunday at 8 p.m. ET on ABC and will be available on demand and on Hulu the following day.