Murray Gold has been a key figure in Doctor Who ever since its revival back in 2005, serving as the composer for all music on the show since then. It's nice, then, that this episode pays a bit of a tribute to him. When the Doctor is playing his guitar in the series finale, the tune is Clara's theme, first used in Asylum of the Daleks. Music plays a big part throughout this series, not just in the work of Murray Gold, with other notable songs including Mr Sandman (The Chordettes), and Yakety Sax by Boots Randolph, better known as the Benny Hill theme tune.