Robert De Niro was left in "excruciating" pain after tearing his quad muscle earlier this month.
The 77-year-old actor had to fly home to New York from Oklahoma, where he had been shooting Martin Scorsese's new thriller Killers of the Flower Moon, after suffering the injury off set.
And speaking to IndieWire about the accident, the screen veteran explained that it happened in a split second as he "stepped over" something.
“I tore my quad somehow..." he sighed. "(It was) just a simple stepping over something and I just went down.
"The pain was excruciating and now I have to get it fixed. But it happens, especially when you get older, you have to be prepared for unexpected things."
Now he's awaiting a procedure to have his leg fixed, Robert added that his pain is "manageable".
And luckily, his role in Killers of the Flower Moon - as powerful cattleman William Hale - is largely a "sedentary" one, so the injury shouldn't affect the movie shoot.
"I don’t move around a lot, thank God. So we’ll manage," he said.
Killers of the Flower Moon, which also stars Leonardo DiCaprio, will be released on Apple TV+, with a premiere date yet to be confirmed.