So I was watching the DVD featurrete about the musical episode, and feel really silly for not realizing that "Emma's Song" is just Mark Isham's OUaT theme with lyrics added.
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"Oh, brilliant" - Thirteenth Doctor
"Half an hour ago I was a white-haired scotsman." - Thirteenth Doctor
"I know exactly who I am. I’m The Doctor." - Thirteenth Doctor
"Two hearts. One happy. One sad." - Thirteenth Doctor