From the Dr. Oliver Sacks he played in Awakenings to the healer he played in Good Will Hunting to the medical student he plays in this film, Robin Williams is having quite the on-screen medical career.

Here Williams plays a character based on real-life Gesundheit Institute founder Dr. Patch Adams who really does believe that laughter is the best medicine as he uses humor to heal his patients.

He’s an outrageous guy, Williams says about Adams who he met prior to filming. He dresses up like a clown, he has a Salvador Dali mustache and very, very long hair, but he’s a doctor.