The movie star made a triumphant return to the theatre after two decades in the Spanish-language drama opposite Carme Elias late last year (11), but he admits he'd rather forget one performance.
He explains, "There's a moment in the play where I have to angrily stab a knife into a table... and I didn't realise that I had cut myself.
"My hand started bleeding and I didn't see it and it was right when we're (Mortensen and co-star) arguing toe to toe and I started waving my hands about and yelling and I'm spraying blood everywhere.
"Usually, she's (Elias) right in my face but she started backing away from me... and I kept following her and she kept backing up to the edge of the stage. She kept looking at my hand and I realised I'm dripping blood.
"I immediately wiped it off on my clothes but I was wearing a white smock, so I ended up, instead of looking like a doctor - which is what I was playing, I looked like a butcher."