Halloween is the one time of year it's okay to reveal that wild, alter-ego usually kept under wraps.
And celebrities love to show off their creative side.
Heidi Klum revealed her Halloween costume last night after teasing her followers on Instagram all day yesterday. She was a fantastic Jessica Rabbit.
Kendall Jenner went out as Karl Lagerfeld.
Gigi Hadid was Sandy from Grease
And Ellen DeGeneres made up her own Kardashian sister - she was Kara. Genius.
