Clarence House has announced Prince William will marry Kate Middleton on Friday, 29 April, at Westminster Abbey.
The couple, both 28, got engaged while on holiday in Kenya in October.
Prime Minister David Cameron said it would be "a happy and momentous occasion" and would be marked by a public holiday.
The Royal Family and the Middletons will pay for the wedding itself, but the taxpayer will meet the cost of extra security and transport.
Westminster Abbey has hosted the weddings of the Queen and Queen Mother and was the venue for Princess Diana's funeral in 1997.
The prince's private secretary, Jamie Lowther-Pinkington, said the couple chose the abbey for its "staggering beauty", 1000-year royal history and its feeling of intimacy despite its size.
He said William and Kate were "calling the shots" on the wedding plans, but had a "rather large supporting cast" to help them.
"Prince William and Catherine have made it very clear that they wish everybody to be able to enjoy the day with them," he said.
"Consequently, the day will be a proper celebration for the nation and the realms.
The BBC reports 29 April was chosen because it fell after Easter and Lent and before a busy political programme in May and June.
The extra holiday will fall in the same week as Easter Monday.