Prince Harry's wedding to American actress Meghan Markle could provide a £500 million boost to Britain's economy as tourists flock to the country and Britons celebrate, according to an estimate.

Harry, Queen Elizabeth's grandson and fifth-in-line to the throne, will tie the knot with Markle on May 19 at Windsor Castle, the royal palace home of British kings and queens for almost 1,000 years.

There were an extra 350,000 visitors to the U.K. in April 2011 when Harry's elder brother William married his wife, Kate, compared to the same month the previous year, according to the Office for National Statistics.