Britney Spears (in-universe)

Britney Spears was a 21st century human singer. One of her songs was "Toxic". (TV: The End of the World)

In early 2005, Steve Hrad played a Britney Spears CD on his boombox in a park, when the Ninth Doctor told him that the song would live on a long time after Steven's death. Shortly after, Steven wrote about his encounter with the Doctor on whoisdoctorwho.co.uk. (PROSE: Have You Seen This Man?)

Irving Braxiatel once asked Jason Kane to buy him some Britney Spears CDs while on a trip to Earth in the 21st century. (PROSE: A Mutual Friend)

Her song "Toxic", a "traditional ballad," was played on Lady Cassandra's "iPod" on Platform One in the year 5,000,000,000. (TV: The End of the World)

Information from invalid sources
Eddie Redmayne once called Britney on the phone to ask her if she knew where Pudsey was. (NOTVALID: Looking for Pudsey)

Britney Spears