During filming of the finale, Peter Capaldi dislocated his thumb during an 'overenthusiastic' take (according to actress Maimie McCoy). She said "...his thumb had completely dislocated - he'd quite instinctively just slipped it back in - and then the colour went from his face."
In a Guardian newspaper piece, a fencing expert commented that Luca Pasqualino's style was "light on his feet and excellent at changing direction. He gets the gold medal from me."
During filming Peter Capaldi found out he got the role of The Doctor (12th) on BBC's hit show Doctor Who (2005).
Writer Adrian Hodges claimed he wanted the Musketeers to bring back "old-fashioned, chivalric, romantic heroes" in what he says is a dirge of TV anti-heroes.
This is the second time Santiago Cabrera portrays a character who exhibits a romantic interest for a queen: in TV series "Merlin" he appears as Lancelot, a future Knight of the Round Table who falls for Guinevere, the future queen of Camelot.