Hollywood party halloween costume greystone manor rihanna
Hollywood party halloween costume greystone manor chris brown rihanna

Leave it up to RiRi to change clothes in the middle of her own party!

Rihanna hosted a Halloween party at Greystone Manor in Hollywood last night, and the "Diamonds" singer walked the red carpet in a demure black dress before changing into a green veil and costume. Could she have been paying homage to her favorite past time?

Once inside, the Barbadian beauty partied with rumored on-again boyfriend Chris Brown, who was dressed as a Taliban soldier, and Basketball Wives star Evelyn Lozada.

Later in the night, Katy Perry's bestie was crowned the Queen of Halloween!

It must be nice to be the pop princess!