Toxic

Toxic was a popular recording made by singer Britney Spears in the early 21st Century on Earth. By the year 5 billion, the song was considered a ballad from Earth's classical era and was played on a vintage jukebox owned by Cassandra shortly before the planet Earth was destroyed. (DW: The End of the World) (As such, "Toxic" could be called the last song heard during the planet's history.)

Behind the scenes

• The shot of the Doctor bobbing his head to the music subsequently has been used in so many fan-made music tribute videos, appearing on websites such as YouTube, that it is approaching Internet meme status.