In the movie Grease she is portrayed by Jamie Donnelly.
Jan is at an average weight and height, has a slightly peach skin tone, black pigtails and baby bangs. Her first outfit was seen in the first scene of the movie with the Pink Ladies; it was a blue blazer with ruffles in the middle, her Pink ladies jacket, and a long yellow checkered skirt with matching sneakers.
Jan is goofy, good-natured, and honest. She's probably the sweetest member of The Pink Ladies, and is definitely the most easy going. She's fun and silly and mostly just wants to have a good time. While the other girls are going through issues and like to cause drama, Jan is just hanging around to enjoy herself and to laugh and have fun with her friends. Jan is carefree and cooky. She's the joker of the group, constantly making jokes and acting stupid. She's weird and wacky, and even though she annoys the other girls, they still love her.