Lady GagaLady Gaga celebrated her 25th birthday yesterday in a very low-key and intimate fashion.

UsMagazine.com reports that Gaga's friends threw her a surprise birthday party at a Mexican restaurant called La Cita Bar in Los Angeles.

She was reportedly dressed in a tight shimmering black dress with her blonde hair styled like a beehive. And with around 60 of her friends cheering on, Gaga took to the stage and sang with the restaurant's mariachi band.

The birthday girl sang several songs including hits by Motley Crue and Madonna, as well as some of her own numbers.