Julia Michaels, Jason Mraz, Lukas Graham & More to Sing Duets With 'American Idol' Top 20

American Idol’s Top 20 will be duetting with some all-stars on Sunday, April 7th.

Following Monday night’s episode, Katy Perry tweeted out the full roster of celebrity guests who will be performing with the contestants. They include Julia Michaels, Jason Mraz, Lukas Graham, Elle King and Shaggy.

Other guests include rock legend Pat Benatar, lovelytheband, Neil Giraldo, country star Brett Young, singer/songwriter Ben Harper and Broadway star Cynthia Erivo.