Doctor Who: 20 Things You Didn't Know About The Tenth Doctor
2. His Final Scenes Were For The Sarah Jane Adventures
Despite The End of Time Parts One and Two being Tennant's final regular appearances as the Tenth Doctor, the final scenes he shot as the character were actually for a different show - Whoniverse spinoff The Sarah Jane Adventures.
The Tenth Doctor was in two episodes of the show called The Wedding of Sarah Jane Smith (a two-parter), attending, well, the wedding of Sarah Jane Smith.
Rather than bringing her a waffle iron, he's actually there to save her from her wannabe hubby, who's actually a trick.
Tennant filmed his scenes for these episodes after he was done with Doctor Who, making them an interesting footnote in his first run with the character.