Cate Blanchett and Bill Nighy have both appeared in productions of The Lord of the Rings. Blanchett played Galadriel in the Peter Jackson films, while Nighy played Sam Gamgee in the BBC Radio broadcast. Both productions also featured Ian Holm.
When Barbara has had her meeting with the headmaster at which he reveals what he knows about her stalking of Jennifer Dodd, she throws up in a school toilet. In the background, on the wall, is written the graffiti: "Babs Covett = nasty old lezza. I want to lick her mangy twat."
Jason Reitman read the script and wanted to direct it. He called up the producers on the phone with the intention of getting the job. The producers answered: "We are in editing right now, but I hope you'll like the film when it comes out."