Lauren Conrad & William Tell: Supercalifragilisticexpialidocious Halloween!

Lauren Conrad and boyfriend William Tell head into Lure nightclub for Matthew Morrison‘s Halloween bash in Hollywood on Sunday night (October 28).

The twosome dressed up as Mary Poppins and pal Bert.

PHOTOS: Check out the latest pics of Lauren Conrad

On her newly revamped website, Lauren unveiled the winner of her costume contest — Breanna as Jack in the Box! Head on over to see how she put her outfit together.

TELL JJJ: What are you going as for Halloween or what did you go as?