Margot Robbie was vacationing with her brother on an island in Croatia when she got the call that the directors wanted her to audition. She had arrived at the hotel at 6 a.m., and needed to catch a flight the same day. She packed everything in 20 minutes and took a catamaran to the main island, then a bus to the airport. She waited in the airport for six hours, flew to France, then got a six-hour flight to New York. When she arrived in New York, she found out her luggage had been lost. However, she got to the audition on time, wearing denim shorts, a t-shirt, and no makeup. When Will Smith arrived late, saying he "was coming from Queens", Robbie said "Yeah? Well, I just came from an island off Croatia and I'm here on time." Robbie believes that reply got her the role.
The sly joke about Australians made by Nicky, in relation to McEwan being an Australian, is an in-joke originally suggested by Margot Robbie to reference the fact that Robert Taylor and she are Australian, and is a gimmick Margot likes to have in her projects, to give her friends and family in Australia a bit of a laugh.
After Ryan Gosling dropped out, the role was offered to Brad Pitt, but he declined, and Ben Affleck, who dropped out citing "scheduling conflicts."