Originally an older actress was going to play Older Amy, but Karen Gillan insisted on playing Older Amy with the aid of prosthetics and it was decided Karen Gillan playing both characters would be more believable. Gillan developed different body-language, vocal range and attitude for the new individual, whose character has changed after being left behind and in danger. To achieve this, Gillan studied with a voice coach and movement coach. Gillan also wore a padding which affected her movement and she spent hours in makeup.
Executive producer Beth Willis insisted that Amy's speech about how Rory was the most beautiful man she ever met made it into the final version.
Older Amy was modeled after Scathach n-'Uanaind, a red haired Scottish warrior woman and martial arts teacher from Celtic mythology.
The cast list for this episode was, until Heaven Sent (2015), the shortest of any full length episode of the modern series. Considering the classic series, it is second only to The Edge of Destruction (1964) for the fewest cast members.
When The Doctor looks for the glasses, a small tape player looking device activates on the TARDIS console and the original Doctor Who (1963) theme can be heard, played backwards.