Zac Efron Reveals How He Tore His ACL at Sundance

Courtesy of Michael Rozman/Warner Bros.

The actor explained how his search for adventure in Utah had painful consequences.

Zac Efron explained how his adventurous tendencies led him to tear his ACL when he visited The Ellen DeGeneres Show on Tuesday.

After the world traveler spoke about visiting the desert in Dubai and cliff jumping in Hawaii, he shared that he tore his ACL while he was at this year's Sundance Film Festival for the premiere of Extremely Wicked, Shockingly Evil and Vile.

While Efron was in Sundance to promote the film, he said that he spent most of the event looking forward to taking advantage of the skiing in Utah. "I was looking forward to the next day where I could go skiing," he said. "My brother and I went cat skiing, which is where a big tractor takes you up on a private mountain and no one skis the snow at all and it was like eight to ten feet of fresh powder."

"I've never skied on fresh powder. I've never used powder skis. I'm a groomed run person," Efron continued as a video of him skiing appeared onscreen. "I'm like, 'Wow, I'm getting good at this.' I'm like flying. I'm gaining confidence. I'm just like looking at the sky and the mountains. 'This is beautiful. I can't believe that I can go this fast on skis,' and I'm just catching the groove."

"I'm just looking around like, 'This is unbelievable.' And I'm like, 'How on earth do you slow down?'" he said as he bent over to demonstrate his fall. "I felt a pop from my ears all the way down to my toes. I didn't really think about it cause there was snow in my face and adrenaline."

Efron realized that he injured himself when he stood up and tried to put his ski back on. "This blade just gave out," he said. The actor was offered to be taken down on a sled, though he opted to ski down the hill on one leg because he "didn't know I had torn my ACL."

The actor also spoke about his grandparents during the appearance. DeGeneres shared a video that Efron posted on Instagram in January to celebrate his grandfather's 91st birthday. The host pointed out that a photo spread of a young Efron appeared in the background of the video.

"That's my grandpa. He's my hero. I don't know where to start with that man. He's the best guy," he said. "He's very interested in the world. He can complete a crossword puzzle — New York Times, like all the way to Saturday. On Sunday he gets a little troubled."

Efron then addressed the poster of himself in the background of the video. "My grandma, may she rest in peace now. She just passed," he said.

After he described his grandmother as "the best scrapbooker," he shared that she would go to stores to buy children's magazines that included posters of him. "She would cut them out and she would make those posters," he said. "Every time I would come to the house as I got older and older, there were just more and more and then I started to realize behind them there were actually — if you lifted up — there were actually more posters."

"One day I went and I wrote, 'To grandma. I love you' on all of them. She hung them all over the house," he shared.