Keanu Reeves has shared details of his brutal kneecap injury sustained while on set for Aziz Ansari’s forthcoming comedy Good Fortune.

Reeves plays the lead in the forthcoming comedy film, also starring Sandra Oh, Seth Rogen and Keke Palmer. Plot details have been kept under wraps and a release date has not yet been announced.

He was spotted walking with crutches and an ice pack wrapped to his left knee earlier this year. Ansari later said that Reeves fractured his kneecap after tripping on a rug in his trailer.

In an appearance on The Late Show with Stephen Colbert, Reeves explained the whole story.

“I was filming a scene with Aziz Ansari and Seth Rogen and we were in a cold plunge,” he recalled. “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?

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“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 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.”

Though Reeves initially thought he was fine, he realised something was wrong when “my knee was blowing up.”

However, he said in response to a question by Colbert that it wasn’t the worst thing that has ever happened to him. “No, the two-level fusion of my spine was.”

Reeves had the procedure just before he began training for The Matrix. “I was like losing feeling, and I was kind of starting to fall in the shower, and I went to see this doctor, and he was like, ‘We need to do surgery right now.’”

It turned out that his spinal cord was squeezed between portions of his spinal discs that were splintered and compressed. He had to wear a contraption around his neck to ensure his spine could fuse properly, which meant his fight scenes had to be rescheduled.

Asked how he had hurt himself, Reeves said: “So many things, motorcycle accidents, racquetball.”

Meanwhile, Reeves recently revealed that he finds himself thinking about death a lot as he comes closer to his 60th birthday.

“I’m 59, so I’m thinking about death all the time,” he told BBC News. Rather than being a negative thing, Reeves said it was “a good thing.”

He went on: “Hopefully it’s not crippling, but hopefully it’s sensitised [us] to an appreciation of the breath we have, and the relationships that we have the potential to have.”