Throughout the movie, Joseph (Luke Treadaway) is frequently asked about the difference between two identical twins who were invited for the wedding ceremony (he even mocks them at some point). In real-life, Luke is the identical twin of Harry Treadaway, who is also an actor.
Felicity Jones (Dolly) worked with Luke Treadaway's (Joseph) identical twin Harry Treadaway on Meadowlands (2007). They played Zoe Brogan and Mark Brogan respectively.
Elizabeth Webster (Betty), Ellie Kendrick (Kitty), and Mackenzie Crook (David Dakin) have all appeared on Game of Thrones (2011). They played Walda Bolton, Meera Reed and Orell respectively.
Felicity Jones (Dolly) and Ellie Kendrick (Kitty) appeared in The Diary of Anne Frank (2009). They played Margot Frank and Anne Frank respectively.
During the shoot, there were three days of heavy snowfall. On these days, the camera could not be pointed at any of the windows in the room.