The Clown at Midnight (1999)

After Kate's friend Monica invites her to help clean up an old opera house where her mother was killed in a play she starred in, she is skeptical. But when the doors suddenly get locked from the outside, she has good reason to be. She starts having visions of her dead mother getting killed down in the basement and everyone starts to see a mysterious clown. When people start dying they decide that they have to get out quick. When the clock hits twelve, someone wants her to be in the final scene with them.