10 Most Heartbreaking Doctor Who Moments

This is a long build up to an incredibly quick regeneration. In but a flash of light we meet Peter Capaldi's 12th Doctor. However, before this we see a Doctor who is aged and dying, but gets a final blast of regeneration energy from a rip in time.

This boost of energy allows him to recover and revert to his younger self, still in the guise of Matt Smith. Clara walks into the TARDIS to find a bowl of fish fingers and custard, the first food Eleven ate and liked. She finds him monologuing and hallucinating a young Amelia Pond. Amy comes to him and gives a final goodbye to her "Raggedy Man".

The Doctor begins the final stage of the regeneration welling up much like David Tennant's Doctor before him, he gives a speech about how we must always move on but remember those before. It's an incredibly poignant moment for one of the more energetic iterations of the Doctor.