Which Celeb Is Sporting Bunny Ears?

One fashionista got busy doing the rabbit. Guess who?

Remember when it used to be a bad thing to have bunny ears in a picture?

Now, it's suddenly chic. Madonna wore them first, and now this tiny fashionista is doing the same at a soiree in Tokyo.

The celeb's sister joined her for the international bash and sported a pair of mouse ears herself.

Think you know who the party animals are? Find out after the jump...

Let's hear it for Ashley and Mary-Kate Olsen!

The twins attended the Opening Ceremony reception party in Tokyo, along with Kirsten Dunst and Jason Bateman.

What do you think of the sisters' animal-inspired headpieces?