Chris Hemsworth - Kristen Stewart's Punch Left Chris Hemsworth With Black Eye

The Twilight actress plays the lead role in the upcoming fantasy film, alongside Hemsworth as The Huntsman.

Filming had to be postponed last month (Oct11) after Stewart tore a ligament in her hand during a fight scene with dwarves, but the star admits she isn't the only one suffering from an injury - she accidentally punched Thor hunk Hemsworth in the face.

During an appearance on U.S. TV's The Tonight Show with Jay Leno on Thursday (03Nov11), she explained, "It made such a sound. It was in a scene. Girls, if you've ever wondered if it (punching) works, it works! It literally spun him right around! I was supposed to miss him...

"I basically knocked him right out of his close up (shot). I was (crouched) down and he was over me, 'huntsman-ing' out, (and I made) just really good contact. And I could hear the cameramen go, 'Woah!'."

But Stewart insists she wasn't proud of herself after accidentally hitting her co-star: "I'm not proud though. Instantly, tears sprung to my eyes. Like, 'Ahh, are you OK?' But it will definitely be in the movie."

Asked if Hemsworth has a black eye, Stewart nodded, adding, "And a big lump on his nose!"