Costume masks of Britain's royal family are flying off the shelves nationwide ahead of Prince William's April 29 wedding to Kate Middleton. And with Britons taking no pains to, well, mask their excitement about the wedding, the bride-to-be's face has been popping up in the most unlikely places.

On the street. At the gym. In the office. And the stores? They're struggling to keep the masks in stock.

"They're flying out the door," said Tony Warner, assistant manager of London's Escapade party store. "They're beating (masks of) Simon Cowell, they're beating everyone else."

More than 120,000 royal masks have shipped already and Mask-arade, the company behind the phenomenon, is taking orders for 20,000 more each day, according to Ray Duffy, one of its founders.

"We thought they were going to be popular, but we underestimated just how popular," confessed Duffy. "It's gone absolutely wild."

Wills and Kate are the best-sellers of course, but the other royals on offer — Prince Harry, Queen Elizabeth II, Prince Philip, Prince Charles and his wife Camilla — are not far behind.

The success has stunned Duffy and his fellow mask men, forcing the Southam, England-based company to double in size and triple the number of contractors to meet the surge in demand.

"We're at absolute maximum capacity to get the orders shipped," Duffy said, adding that employees are logging 12-hour days and six-day work weeks. The company has already stopped taking large orders so it can guarantee delivery before the wedding.

And it's not just enthusiastic locals. Mask-arade is shipping British royal faces all over the world — to the United States, Australia, Scotland, even Vietnam.

The founders launched the business in 2008 to make personalized masks for parties, but when requests came in for celebrity faces, they were happy to oblige. The company offers about 100 masks total.

(Read by Renee Haines. Renee Haines is a journalist at the China Daily Website.)