Toby Young, the man around whom the film is based, was banned from the set, as he was reportedly annoying cast members, and interrupting Robert B. Weide as he tried to direct scenes.
The scene where Sidney (Simon Pegg) asks an actor "Are you gay?" is based on Toby Young doing the same to Nathan Lane regarding his role in The Birdcage (1996).
According to the book of the same name, the scene in the elevator in which Sydney Young quips to a model that the elevator door will take your arm off if you're not wearing Prada, and the model curtly sniffs, "I *am* wearing Prada," really happened to Toby Young during his time working for Vanity Fair Magazine in New York.
In the scene where Sidney first meets Sophie Maes, the man standing directly next to her on the right side of the screen is Brian Austin Green, who was at the time of filming, Megan Fox's fiancé.
Megan Fox was cast in her role before Transformers (2007) was released. Director Robert B. Weide had hoped he would have been the one credited with uncovering this new talent, and so after Transformers (2007) was a big hit, and Fox quickly becoming an international sex symbol, he remarked he was disappointed, not for her, but for the fact he wasn't the one who first brought her to the cinematic stage.
Stephen Woolley: Producer has a cameo as one of the members of the queue behind Sidney at the airport. He is the man with long hair wearing dark glasses.