MasterChef Australia judge Jock Zonfrillo jokes managing Katy Perry on set an 'absolute nightmare'

Katy Perry with Jock Zonfrillo. Photo / Network Ten / Supplied

MasterChef judge Jock Zonfrillo – aka "daddy" – has aired his thoughts about Thursday night's chaotic episode with superstar Katy Perry.

Zonfrillo, 43, looked mortified when the US singer, who surprised contestants with her appearance during the immunity challenge, asked him to cut her meat for her and said: "Put it in my mouth daddy!"

"Look, it's embarrassing," Zonfrillo told Studio 10 yesterday via a video chat.

He added trying to keep Perry under control during filming was an "absolute nightmare".

"Katy Perry is a dynamo. She came in the kitchen, she broke all the rules," he said.

"And the twist was actually on the judges, because trying to control her and contain her was an absolute nightmare.

"She was hilarious, absolutely hilarious, but she didn't stick by any of the rules, which we loved, of course. It made for a hilarious episode.

"And you know what, she's been singing the theme tune for MasterChef (Hot n Cold) for the last 12 years, so the least we could do was have her on for an episode, I reckon."

It comes after contestant Reece Hignell told news.com.au Perry's presence on screen was exactly what she was like in person.

"She walked in and did not leave," he said.

"The whole time she was there, she was on. She didn't leave the floor once.

Fans praised the pop star's appearance. Photo / Network Ten / Supplied

"She spent the whole time walking around trolling us, but it was the most endearing thing," Hignell said.

"She was like, 'Oh, is this cake going to cook in time?' I was like, 'Katy, it's got half an hour to cook,' and she said, 'Hmm, cakes take longer than half an hour.' I was like, 'Leave me alone!'".

After filming the guest spot, Hignell said the singer hung around for a quick chat with the contestants.

"She stuck around briefly afterwards and we did a few publicity photos," he said.

"I had a chat to her for about five minutes. We were just chatting about the competition and she was in disbelief that we have to walk in every day and cook without a recipe.

"She was shocked that we had to come up with all of our ideas on the spot, so that was really cool that she gave us a bit of respect."