Nicole Kidman’s workout routine is rather “intense,” according to her Family Affair costar Joey King!

“She taught me the most epic, awful butt workout I’ve ever learned in my life. It was, like, so intense,” Joey, 24, shared during an appearance on The Tonight Show Starring Jimmy Fallon on Monday, July 8. “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.”

She went on to describe some of the maneuvers involved in the workout routine, which made the audience laugh.

“It was these donkey kicks and the rainbows and the fire hydrants and all these other [moves]. But you have to keep your leg in the air for, like, 12 years. It’s so hard,” Joey added.

The Kissing Booth actress has maintained a great friendship with Nicole, 57, after filming and still attempts to practice the workout routine on her own on occasion.

“I do it still because it’s the most effective workout, so I send her photos when I do it. I’m like, ‘Call an ambulance, love you!'” Joey said.

Family Affair stars Nicole as Brooke Harwood, the mom of Joey’s character, Zara Ford. Nicole’s character begins a romance with Chris Cole, played by Zac Efron.

Joey shared that Zac, 36, also helped her beef up her fitness regimen when they worked together on the Netflix rom-com.

“He was also, again, so fit, and he helped teach me about my protein intake,” she explained. “He’s very helpful with the wellness tips.”

Nicole Kidman’s 'Epic' Butt Workout Is Revealed
Araya Doheny/Getty Images for SAG-AFTRA Foundation

The California native admired both of her costars’ glamorous Hollywood appearances.

“Her and Zac, they’re both, like, so hot,” Joey said. “They’re so hot. They’re the fittest people I’ve ever met. So I became a bit of a tubular gym rat on the set.”

Joey loved working on the movie with her teen idol, Zac, and she’s not afraid to show it.

“Zac was my everything when I was younger, and you still are, Zac,” she said during an interview with ETalk. “There’s so many moments that are pinch me over the years and this is definitely one of them.”

Nicole and Zac previously played love interests in 2012’s Paperboy. The High School Musical alum “jumped” at the opportunity to work with the Oscar winner again.

“I jumped. I think we both kind of did. We jumped at it,” he told People in an interview published on June 29. “It was like, this is perfect. What better way to reconnect? And we get to have fun.”

Zac had nothing but good things to say about working with Nicole this time around.

“I’m still so enamored with Nicole,” he gushed. “There’s a part of me that pinches myself when I realize who I’m working with a lot. I think that was more pronounced during The Paperboy because I was a lot younger. I was very nervous back then.”