Mayer 'serenades fan on birthday'

John Mayer performed an impromptu show for a fan on her 18th birthday in Los Angeles.

The singer, who is reportedly still 'pining' over ex-girlfriend Jennifer Aniston, was dining out with his brother and friends when he was spotted by a group of his followers enjoying a birthday celebration.

After the set of girls "started swooning and screaming", Mayer sang 'Happy Birthday' and gave the teenager a kiss on the cheek, reports People.

Mayer was recently forced to deny that he was dating actress Scheana Marie after the pair were spotted at an LA eatery.