Katy Perry & John Mayer Party & Perform Together Ahead of New Year's Eve!

John Mayer and Katy Perry partied like 18-year-old's... clubbing till 4:30 AM Thursday, and that's after John raged on stage at a concert earlier in the day with the Grateful Dead. They entered the same auto after exiting the venue.

Perry sported a white, short sleeve maxi dress with a colorful print while Mayer bundled up in a black wool coat.

Katy and John at an event early in their relationship. Source Getty

Perry and Mayer last sparked speculation that they are back on several months ago, when they attended Girls stars Allison Williams' wedding.

Things are looking as if the couple will be spending New Year's Eve together. Or maybe they're just good friends who get tipsy together!