John Mayer celebrates Katy Perrys 28th birthday at costume party

After Katy Perry spent last weekend celebrating John Mayers 35th birthday, the musician appeared to be returning the favor on Friday when he accompanied his lovely lady to a costume party in honor of her upcoming 28th birthday.

Just Jared reports that Perry showed up to the party, located at Los Angeles Magic Castle, wearing a sexy vampire costume, while her beau wore a vampire hunter get-up, complete with a prosthetic nose and chin.

According to Us Weekly, other A-list celebs in attendance were Kristen Stewart and Neil Patrick Harris, as well as Diane Warren and Americas Next Top Model star Johnny Wujek.

And the fun-filled, Halloween inspired bash was also for a great cause. Perry asked for donations to support the David Lynch Foundation for Transcendental Meditation instead of gifts. But it seemed the star had only one thing on her mind the whole night John.

A partygoer told Us, They were in their own world. She didnt even talk to her friends much. It was just her and John. Shes obsessed with him. She said hello to people but then went right back to him.

Photo Courtesy of INFDaily.com

Follow us on Twitter! Follow us on Facebook!