Katy Perry and her boyfriend John Mayer dress up in fun costumes for her birthday bash held at The Magic Castle on Friday  in L.A.

Katy celebrated her upcoming 28th birthday by dressing up as a vampire, while John, who turned 35 earlier in the week, wore a prosthetic nose and chin for his zombie hunter costume.

Check out the pics HERE

FYI: Katy turns 28 on Thursday (October 25). Happy early birthday!!!