King Charles III and Queen Camilla appear on American Idol with judges Katy Perry and Lionel Richie

King Charles III and Queen Camilla made a surprise appearance on Sunday’s episode of American Idol amid his historic coronation festivities.

The royals appeared as American Idol judges Katy Perry and Lionel Richie, who were in the United Kingdom to perform during the Coronation concert, appeared virtually to check in with host Ryan Seacrest, 48. 

Ryan asked how the were enjoying the historic events.

‘What a party,’ said Lionel, 73, wearing an all-black outfit including an embellished sequin jacket. ‘It was unbelievable.’

Katy, 38, was by his side wearing a strapless green dress with a large pearl necklace and matching earrings.

‘It was incredible and we’re here for the coronation concert at Windsor Castle,’ Katy said.

‘Now we are trying to figure out what we can do to bring something different to the show,’ Lionel said. ‘So, …I have a surprise.’

Just then King Charles, 74, wearing a blue suit, and Queen Camilla, 75, wearing a long blue jacket walked out and joined them. Katy appeared to bow down.

‘Oh goodness,’ Katy said.

‘I just wanted to check how long you will be using this room for,’ King Charles said laughing. ‘I just wanted to check.’

Queen Camila smiled.

‘We have to give up the room up right away,’ Lionel said.

Lionel thanked him for coming.

Coronation performers: ‘Now we are trying to figure out what we can do to bring something different to the show. So, …I have a surprise,’ said Lionel who was a performer at the coronation celebration along with Katy

Dressed up: Katy wore a lovely green strapless gown and Lionel looked sharp in an embellished sequin suit

American competition: The royals appeared remotely on the ABC show as guest judges Alanis Morissette and Ed Sheeran looked along with regular judge Luke Bryan

‘No, thank you for your brilliant performance and thank Katy as well. It really was ‘ King Charles said.

King Charles said it was ‘great to have you both here.’

‘Are we making too much noise?’ Katy asked Queen Camilla.

‘I understand there is a party,’ Lionel said.

‘Ah you have heard about that,’ King Charles said.

‘Well, you are throwing a party right next door,’ Lionel said.

‘Ah, that’s right,’ King Charles said. ‘Had we better take you to the party but you’re busy with all these other things.’

‘As soon as we finish, we are coming to the party,’ Lionel said.

Funny side: ‘Ah, that’s right,’ King Charles said as he showed his funny side. ‘Had we better take you to the party but you’re busy with all these other things’

Party time: ‘As soon as we finish, we are coming to the party,’ Lionel said

Good times: Queen Camilla flashed a smile during the fun segment with King Charles III

‘We are coming to the party,’ Katy said.

‘Well, you deserve it,’ King Charles said. ‘Bless you.’

‘Thank you so much,’ Katy said. 

‘We love you,’ Lionel said as King Charles walked off. ‘Congratulations.’

‘God bless you,’ Katy said.

King Charles and Queen Camilla then walked off.

‘That is the royal treatment. I found myself standing up straighter while I was watching that right there,’ Ryan said.

Alanis Morissette, 48, and Ed Sheeran, 32, filled in as judges for Katy and Lionel during the season 21 episode that featured performances by the top eight singers.

American Idol will return Sunday on ABC.