Royal Wedding Fans Already Camping Out

VIDEO: Nick Watt talks to two Britons who have set up four days in
WATCH The Royal Wedding: Die Hard Fans Camping Out

Princess Diana superfan John Loughrey will sleep on the sidewalk for the next three nights. "I'm here now and I'm here to stay," Loughrey said outside Westminster Abbey. "Diana would be very proud of her son."

Loughrey Is a Longtime Fan of Princess Diana

Loughrey has brought his sleeping bag and will be using the sidewalk as a mattress. Gwen Murray at least brought a chair.

"I'm a bit worried about the weather," Murray, who has also taken up a position outside the abbey, said.

Watch a special '20/20' Thursday at 8 p.m. ET for a behind-the-scenes look at the life that awaits Kate Middleton and join us again at 4 a.m. Friday for ABC News' live coverage of the Royal Wedding with Diane Sawyer and Barbara Walters

Inside Westminster Abbey, the stage manager of Simon Cowell's "X Factor" will reportedly direct TV coverage.

"We'll have close-ups of Kate Middleton right there," Duncan Larcombe, royal editor of the Sun newspaper, said. "So, as a television event, this is going to be unprecedented."

This is a big operation: 60 cameras in total, dotted all over the abbey, capturing intimate reactions of the queen, Middleton's parents and even the Beckhams.

And people are betting on nearly every aspect of the wedding: The color of the queen's hat, the dinner menu. You name it, bets are being placed.

For the color of the queen's hat, yellow is the favorite with odds of 11 to 10.

As for the likelihood of Middleton's arriving at the abbey in rain, that's at 5 to 2 odds. Bets are also on for the balcony kiss to be under an umbrella.

And a mystery woman has staked $10,000 that Middleton will wear the queen's Russian fringe tiara. If she does, the gambler will take home $120,000.

"Do you think she's right?" Larcombe asked. "Well, if she's not, she's mad. The bookies last night said she's either got inside information or she's mad as a brush.

"It's a fairly clear sign that somebody somewhere knows something about what Kate's going to wear on her head," Larcombe said.