Joey King Says Nicole Kidman Taught Her the 'Most Epic, Awful Butt Workout' She's Ever Tried

"You have to keep your leg in the air for, like, 12 years. It's so hard," the 'A Family Affair' actress said on 'The Tonight Show Starring Jimmy Fallon'

Joey King has Nicole Kidman to thank for improving her fitness game!

The actress, 24, revealed that Kidman, 57, taught her “the most epic” butt workout on the set of their new Newtflix film A Family Affair during an interview on the July 8 episode of The Tonight Show Starring Jimmy Fallon.

"She taught me the most epic, awful butt workout I've ever learned in my life. It was so intense," King said of her costar. "I was like, 'I'm a youngster. I can hang. I'm young, and I'm agile' — I thought I could hang, but I couldn't hang."

King said the workout included “all these donkey kicks and the rainbows and the fire hydrants,” among other moves. “But you have to keep your leg in the air for, like, 12 years. It's so hard," she added.

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Related: Nicole Kidman, Joey King and Zac Efron Pose for Photos at A Family Affair Premiere in L.A.

Despite the strenuous moves, King said she still incorporates Kidman's butt workout into her fitness routine.

“I do it still … I send [Kidman] photos when I do it I’m like, ‘Call the ambulance, love you!’ ” she told host Jimmy Fallon.

In A Family Affair, King plays a young woman called Zara navigating her mother (Kidman) falling for her famous actor boss (Zac Efron).

King also told Fallon about her longstanding love for her costar Efron, 36, stemming from a childhood obsession with the former teen actor.

“I love him. I grew up with his face on everything I owned,” she revealed.

"Did you have a Zac Efron lunchbox or something?" Fallon, 49, asked.

Related: Joey King Recalls Childhood Obsession with A Family Affair Costar Zac Efron: 'Had His Face on Everything'

"Among everything else!" replied King. "All the merch that I could get my hands on and I was one of those kids, I was like, ‘Mom, the movie is going to be on at 8/7 Central. I don’t know what that means but I have to be home to watch … I had his face on everything and I was such a fan."

She added of Efron, "He was so, so fantastic.”

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King also shared that she would sing the High School Musical 3 song “Scream” to Efron on set, which the actor was gracious about.

“He would sing along with me and that was so great. And he was also, again, so fit. He helped teach me about my protein intake. He’s very helpful with the wellness tips,” she recalled.

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