Joey King reveals tough workout lessons from Nicole Kidman

Nicole Kidman has a very tough fitness routine for her buns, and she taught her A Family Affair co-star, Joey King, how to do this, but this was a little too much for the young star.

Giving an insight into the fitness routine of The Tonight Show Starring Jimmy Fallon, the actress said, "She taught me the most epic, awful butt workout I've ever learned in my life. It was, like, so intense," adding, "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."

Joey explained the exercises involved in the fitness routine, "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."

Though the film was finished, the 24-year-old said she still followed this fitness routine.

"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!'" he shared.

In addition, Joey raved about Nicole, saying she was "just a sweet and silly, fun person," noting, "She's such a girl's girl."