When planners at the Ritz-Carlton decided to throw a royal wedding viewing party with big-screen TVs and a 5 a.m. start time Friday, they thought they might get a few dozen diehard royal-watchers. Max.

Instead the hotel in Northwest Washington ended up with a sellout crowd of 250 guests — all wide awake and dressed to the nines — including a local Democratic powerbroker with her dog in a bridal gown and a lady wearing a homemade hat covered in Twinings tea bags.

“Thank God you are doing this,” one guest declared when she bought her $40 ticket. “I have a tiara, and I never get a chance to wear it.”

The over-caffeinated guests who turned up to watch the nuptials of Prince William of Wales and Miss Catherine Middleton dined at rose-strewn tables on traditional English fare such as porridge and scones with clotted cream. They ­“oohed” and “ahhed” at all the key moments during the ceremony, broadcast at 6 a.m. on large screens in the hotel ­ballroom. They applauded when Middleton appeared in her lace-trimmed wedding dress and applauded again when she emerged on the arm of Prince William outside Westminster Abbey, newly married.

“It’s so exciting and uplifting,” said Jody Milanese, 33, an Arlington resident who works in government affairs. “This is a moment when you step away from it all . . . a kind of ‘where were you when’ kind of experience.”

Arlington County resident Keyana Corliss is crazy about everything royal, so it was no surprise that she dragged herself out of bed at 4 a.m. and donned an orange-striped Kate Spade hat for the occasion.

Corliss, a 25-year-old consultant, said she is “obsessed with all things royal . . . and this wedding is the Super Bowl of royal obsession.”

Milanese, Corliss and others had good reviews for Middleton’s satin and lace wedding dress designed by Sarah Burton for Alexander McQueen. The dress had been a closely guarded secret until the very end. Corliss deemed its last-minute unveiling “fabulous.”

Also on the “fabulous” front was Mame Reiley, the chair of the Democratic National Committee’s women’s caucus and adviser to governors and senators. Friday, she showed up at the Ritz with her pug, Lucy, in tow. Lucy was dressed in a pint-size wedding dress and was sniffing around another canine guest, a Yorkie named Prince William.

“Lucy, honey, put on your veil,” Reiley said, pulling the pug away from the other dog. “I told her no sex before the wedding.”

But seriously: “It’s a special occasion, a happy occasion. It’s exciting. And that’s coming from an Irish woman,” Reiley said.

Many, such as Reiley, spoke of fond — and at times poignant — memories of the wedding of William’s parents, Princess Diana and Prince Charles, 30 years ago.

“This is bittersweet to me,” said Susan Nixon, a native of Britain who runs a local public relations firm. “It brings back losing Diana. It’s sad she is not here to enjoy it. But I also think it is an uplifting moment for everyone.”

Karen Tinsky, 36, a lawyer from Chevy Chase, still remembers her mother waking her up that day in 1981 when she was just 6 years old.

“That is a lovely memory. I wanted to create that memory for my daughter,” she said, hugging Elle, 4, who was dressed in a blue Cinderella dress.

Lauren Schaffner, Caroline Puckowski and Elizabeth Slattery — all 20 and Georgetown University students — weren’t alive when Diana got married, but they were eager to watch this wedding. They even tried, and failed, to borrow hats from the Georgetown theater costume shop for the occasion. The trio watched and applauded approvingly when the newlyweds climbed into an antique carriage for their ride to Buckingham Palace.

“It’s like such a perfect fairy tale,” sighed Puckowski, a sophomore from Connecticut majoring in international politics. “Who doesn’t want to be Kate Middleton right now?”

The three agreed that their favorite moment was at the altar when William looked glowingly at his bride and said, “You look beautiful.”

Then, finally, after three hours, there was the balcony kiss. Or rather, two kisses.

“It was wonderful,” Slattery said afterward. “Definitely worth getting up for.”