THE FASTEST CREATURE ON EARTH, it seems, is either a racehorse, a jaguar or a TV movie producer on deadline. Consider Princess in Love, the story of Di's five-year dalliance with army officer James Hewitt, which CBS will broadcast May 15. Once the network decided to go forward in February, the movie, based on the 1994 bestseller by British author Anna Pasternak, got written, cast and shot in seven weeks. How did they do it? Answer: by cutting corners and making up for one horrendous technical mistake.

There was, for example, no worldwide search for the perfect Diana. In fact, there was not even an L.A.-wide search before Julie Cox signed on just days before cameras were ready to roll near the Scottish border. Cox (Tales from the Crypt) is no body double for Di, being brunette (they dyed her hair) and, at 5'4", six inches shorter. And she's oblivious to Windsor-mania. She never read the book, she says, because "I thought I would hate it. I thought, 'If I read it, I'll have a hard time taking the script seriously' "

At the hurried fittings, the costumer was "tearing her hair out...there was a lot of screaming and shouting going on," producer Janet Faust Krusi says. Christopher Villiers, who plays Hewitt, helped by using the same boots he had worn as a Gestapo officer in The Little Riders and as a Napoleonic soldier in Sharpe's Rifles.

You have to give the cast and crew credit for muddling through. At one point, a camera assistant reloaded an already-shot reel, ruining an entire day's footage. (He left shortly afterward, says the production manager: "He was the first to say, 'I don't feel comfortable here.' ") But that was as bad as things got, thanks in part to Pasternak, who spoke up when she noticed the script had Di and Hewitt jumping into a Jacuzzi. "I had to explain," says the author, "that we don't do that in England."