Performances of the Shakespearean play are taking place at the New York park's Delacorte theater.
"(Hathaway) and Audra McDonald were doing the first act when it just wandered onstage. The audience started laughing and gasping, and it wasn't a funny scene," a witness told the New York Post. "Then the raccoon wandered off, but the girls had no idea what had happened until later."
The show is slated to run through July 12.