Actor Jake Gyllenhaal had to visit a Los Angeles emergency room Wednesday morning after punching a mirror on the set of his new film Nightcrawler.

A source on the set of Nightcrawler source told People.com, "Jake flipped out. His character was looking into a mirror during the scene and punched the mirror in anger and broke it, cutting himself so bad he had to be taken to a hospital."

The 32-year old actor received several stitches in the emergency room.  The reason for the incident was reportedly chalked up nothing more than an intense 18-hour shooting day.

"The scene was emotionally charged and his character was talking into a mirror and he got so into it, he banged his hands against the mirror and it broke and cut him," the source close to Gyllenhaal says. "It was all the scene and not because he was mad about anything else."

The traditionally buff star has also been focused on losing 20 lbs. for his role as a crime-scene reporter in the upcoming drama, so maybe he just wanted carbs!

He also could have been listening to ex-girlfriend Taylor Swift's album Red.

Gyllenhaal returned to set later that day.