Tim describes his mother more like a Bernard than a Mary. Richard Curtis always tries to include a Bernard character in his movies. The inspiration comes from Bernard Jenkin, the Tory MP for North Essex and former shadow defence secretary. Mr Jenkin's wife is a former girlfriend of Richard Curtis.
Despite the film being set in England, none of the three actors who play the main love interests in the film are actually English. Domhnall Gleeson is Irish, Rachel McAdams is Canadian and Margot Robbie is Australian.
Tim passes by Abbey Road Studios when he arrives in London. For decades, the logo of the music company EMI could be seen above the name of the studio. In 2013, the EMI logo was removed above the studio name because the company was sold to Universal Music in September 2012, and, to comply with international regulators, EMI's European operations were sold to Warner Music in 2013. However, the studio was one of the operations that Universal Music was allowed to keep, but no logo of the new owner was put in place of the old EMI logo.
The trivia items below may give away important plot points.
This is one of four movies in which Rachel McAdams stars as the love interest of a time traveler. The previous ones were The Time Traveler's Wife (2009), in which she played the titular wife to Eric Bana's character and Midnight in Paris (2011), in which she played the fiancée of Owen Wilson's character. In none of these movies does McAdams's character get to participate in time-travel herself. In both 'About Time' and 'The Time Travelers Wife' she is proposed to in the same exact way, while in bed. She also stars in 'Doctor Strange' (2016), in which she plays a time manipulating doctor's love interest.
The film takes place in the span of around 8 or so years. Tim and Mary's marriage is around 3 years after the film starts, and Posy is seen entering reception at the end of the film, in which she would be 5 years old.
Tim discovers that if he travels back in time to a point before his child has been born, then he will end up with a different child to the one he knew. Near the end of the film both Tim & his father travel back in time to when Tim was a child himself, yet this does not change any of his 3 children because they didn't change anything in the past.