When it comes to her goofy getups, everyday can be like Halloween for Lady Gaga.

But for the annual Halloween holiday, the singer, 24, Tweeted that she was "going to be...a little monster." And she didn't let fans down.

Hitting a bash in Belfast, she sported a Cruella de Vil costume. See which costumes other celebs wore on Halloween.

Women dressed as Dalmatians followed her.

Of course, her Disney villain costume wasn't complete without a few accessories: She kept a fake gun in her coat and had fake blood plastered over her chest. She also sported a black-and-white wig and oversize sunglasses.