Keanu Reeves revealed on “The Late Show” that his kneecap “cracked like a potato chip” when he was injured on the set of “Good Fortune,” the upcoming comedy movie that’s written and directed by Aziz Ansari. The action icon stars in the film opposite Ansari and Seth Rogen. Reeves was photographed on the set during filming using crutches.

“I was filming a scene with Aziz Ansari and Seth Rogen and we were in a cold plunge,” Reeves said. “I was loving it, I was standing there, and we finish the scene, and you know when you’re cold and you’re [shuffling]? I had a bathing suit and a towel, and you put it over your head and you do the cold shuffle?”

“I’m doing the cold shuffle in this room that had protective carpets down and then, just here, there was like a little pocket, and my foot got caught in the pocket in the shuffle, and then I went [down], but [my knee] didn’t follow,” he he continued. “And then, in slow motion, I went falling. My arms came out, but then my knee failed because it’s got some stuff, and I spiked it. And my patella — kneecap — cracked like a potato chip.”

Reeves originally thought he was not injured, but then “my knee was blowing up” and he knew something was wrong. Given his status as an action movie legend thanks to “The Matrix” movies, “Speed” and more, Reeves quipped about the injury: “Comedy’s hard, man.”

Ansari praised Reeves at CinemaCon earlier this year for being “such a trooper” and continuing to film the movie despite the knee injury. The writer-director says the accident occurred about 15 days into filming the comedy.

“He still filmed everything except some scenes where he needed him to do salsa dancing,” Ansari said. “He was like, ‘I’ll do it!’ We’re like, ‘Keanu, calm down. We’ll do the salsa dancing once your knee’s healed.’”

“Good Fortune” will be distributed by Lionsgate but currently does not have a release date yet. Watch Colbert’s full interview on “The Late Show” in the video below.