SPOILER: Series 31 Casting.

From denofgeek.com: Highlight to read SPOILER: It's been confirmed that among the guest stars for the next series of Doctor Who will be Bill Nighy. He's going to be appearing in the episode written by Richard Curtis, which itself is going to see The Doctor meeting up with Vincent van Gogh (who's going to be played by Tony Curran, of This Life fame). Digital Spy is now reporting, however, that Bill Nighy will slot into the episode, playing a curator of a van Gogh exhibition.