Originally Mark Sheppard was to wear old age makeup in order to play the 2011 version of his 1969 character. Instead, at Mark's suggestion, William Morgan Sheppard (Mark's father) was cast for the part. The pair had also played two versions of the same character about a year earlier in NCIS (2003).
This episode is dedicated to Elisabeth Sladen, who died a few days before its original airing. The episode's broadcast on BBC One was immediately followed by the airing of My Sarah Jane: A Tribute to Elisabeth Sladen (2011) on CBBC (the home network of The Sarah Jane Adventures (2007)).
When on the TARDIS, the Doctor remarks on how Sundays are boring. The Tenth Doctor said the exact same thing to Donna in Silence in the Library (2008).
Alex Kingston had to genuinely slap Matt Smith several times in a scene because it was difficult to fake. Kingston recalled that after a few takes, Smith got red cheeked and grew frustrated at having to do the sequence over and over again.
Even though Mark Sheppard is an English actor, this was his first appearance in a British-made television show. And, he plays an American character, unlike his appearances on American television, where he usually uses his natural British accent.