American Idol will replace Katy Perry with a major celebrity.

A "big-time" talent will temporarily replace Katy Perry on 'American Idol'.

The 38-year-old singer and her 'American Idol' co-star Lionel Richie will play at King Charles' coronation concert in May, and Luke Bryan has promised some big-name replacements on the TV show.

Luke, 46, a judge since 2018, told 'Entertainment Tonight': "It's big time. It's huge. Fill-in contestants have used their songs several times. Much more!"

The much-anticipated Windsor Castle performance will include Katy and Lionel, 73. Katy said she's "so grateful" to sing at the occasion.

The pop artist, an ambassador for one of the monarch's organizations, is excited about the show.

"It was very regal," Katy told ExtraTV of her invitation. Loved it. "It was very lovely and I was so thrilled to have the honor since I am an ambassador for the British Asian Trust,

which focuses on stopping child trafficking, which is a significant problem of our day and connected with all my principles.

"I'm also an ambassador for Unicef. And as a mother I know first-hand these innocent children need help, they need to be helped. So I'm just going there as an ambassador and they asked me to sing and it all aligned."