Britney Spears & Iggy Azalea officially launch new song in taxi cabs

Pop fans keen to hear Britney Spears and Iggy Azalea's new song, Pretty Girls, can do so early on Sunday (03May15) by booking an Uber cab in Los Angeles.

The taxi firm is giving fans an exclusive sneak listen of the song to anyone booking a Britney branded SUV between 3pm and 9pm local time. After that, the song will officially be released.

Furthermore, five lucky fans will win a pair of tickets to an upcoming Britney: Piece of Me concert in Las Vegas and a meet and greet with the pop icon - just by booking an Uber cab.

Spears announced the initiative via Twitter at lunchtime, writing, "So @Uber & I are bringing #PrettyGirls to you! Request a 'Bee' ride in LA @ 3pm PT to hear it."

The new song has already leaked online prompting both singers to urge fans not to listen to it until the official release on Sunday evening.

Britney wrote, "I know some of u have already heard it but hold out just a little longer & the song will officially be out later tonight!"