John Mayer Says ‘Happy Birthday’ to Jen Aniston with a Song

Recent Grammy winner John Mayer, 31, is giving his girlfriend/sleepover buddy Jennifer Aniston quite a singular gift for her 40th birthday: A song!

Sources say that Mayer wrote a ditty just for Jen and plans to serenade her with it.

“He did write a special song just for her for her birthday,” a source confirmed to People.

Mayer has the chops to back up his choice of gift.

He won five Grammys on Sunday night, for Best Male Pop Vocal Peformance among others.

No word on whether Mayer has sung her the song yet. Aniston’s actual birthday is tomorrow, but she was reportedly thrown a birthday party last Saturday night with best friend Courteney Cox and Cox’s husband David Arquette as rumored guests.

Could Mayer have sung for her then? Or was he holding out for more intimate surroundings with just the two of them on her actual birthday?

Those “intimate surroudings” probably wouldn’t be at her house, though, seeing as he just expressed annoyance with her $15 million “green” makeover.

Wherever he ends up busting out his special gift to Aniston, Mayer has a solid track record with writing songs for the women in his life. His 2002 smash hit “Your Body Is a Wonderland,” rumored to be about former love interest Jennifer Love Hewitt, nabbed the singer a Grammy for Best Male Pop Vocal Performance.