Katy Perry and her boyfriend John Mayer dress up in fun costumes for her birthday bash held at The Magic Castle on Friday (October 19) in Los Angeles.

The 27-year-old singer 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.

Also in attendance at the party: Katy‘s brother David Hudson, stylist Johnny Wujek and his boyfriend Ricky, jewelry designer BFF Markus Molinari, Raising Hope star Shannon Woodward, DJ Mia Moretti, entrepeneur John Terzian, musician Blue Hamilton, actor Matt Dallas, producer David Ranes, musician Ferras, singer Sarah Hudson, and radio personality Karli Henriquez.

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

30+ pictures inside of Katy Perry and John Mayer at the birthday bash…