Although Katy Perry Turns 28 on Thursday, her birthday festivities started over the weekend! Perry brought in her 28th with family, friends, and some famous faces such as boyfriend John Mayer and get this Kristen Stewart!!! Where was Rob?! Click below to see pictures of the spooky birthday bash!

Eloisa Melo

Katy Perry will turn 28 this Thursday, and celebrated her upcoming birthday over the weekend by combining some of her favorite things this month: Halloween spookiness and her on-and-off man, John Mayer! The pop star had a MASSIVE costume party Friday evening at The Magic Castle in El Lay, during which she dressed up as a very SEKSI Vampire, while her man for the moment opted for some Zombie hunting threads!

And guess who else showed up for the festivities?! Kristen Stewart, who apparently decided to leave Robert Pattinson at home for the night while she pAArtied with friends!

Perez Hilton