Katy Perry snaps sexy Santa pic of boyfriend John Mayer

Merry Christmas indeed, Katy Perry! The "Hot N Cold" singer posted a pic on Twitter of her boyfriend, John Mayer, on Tuesday (Dec. 25) looking sultry in a Santa suit.

"Santa Baby," Perry writes along with the photo. (Cue punny jokes about Santa leaving packages under her tree.)

We're assuming these two had a happy holiday together. A source tells People that the couple celebrated at Perry's house, where they spent the day with her family. And it sounds like things might be serious with the on-and-off duo.

"They've spent a lot of time together and really enjoy each other's company," says the source. "John is entirely focused on Katy."