Charlize Theron suffered with a torn ligament for two whole months without realising.
The actor shared her misfortune with Jimmy Kimmel during a recent appearance on his talk show after she was questioned about the hand-cast she was wearing.
"It's not as cool as I thought it was going to be," Theron said. "This is so stupid. I did an action movie and I tore the ligament off the bone fighting. I messed up my elbow, as well."
The movie in question is The Old Guard, based on Greg Rucka and Leandro Fernández’s comic of the same name, and it follows a captain leads a small group of soldiers working as mercenaries through the ages.
"I've been walking around with this injury for two months. How badass is that?" Theron told the talk show host. "I didn't know that it was anything. I just was like, 'Toughen up. Come on.'
“And then I was told by a doctor that it was basically just floating around and I was like, 'Oh, that's interesting. That's why I've only been using these four fingers.'"
Read more: Actors who suffered bad injuries on set
The film is directed by Gina Prince-Bythewood and stars KiKi Layne, Marwan Kenzari, Matthias Schoenaerts, and Chiwetel Ejiofor.
Theron plays Andromache of Scythia, the captain of this immortal mercenary team, who find it harder than ever before to keep the secret of their never-ending life as they face off against a new immortal foe.
Rucka is penning the script for the movie which will stream on Netflix, while Theron gets to add another badass action hero to her bow.
The actor has previously played the impressive Furiosa in Mad Max: Fury Road and elite spy Lorraine Broughton in Atomic Blonde.
Theron’s next release is the new animated movie The Addams Family in which she voices the role of Morticia.
The Addams Family is released in UK cinemas on 25 October.