Prince Charles, heir to the British throne, on Thursday announced that he would marry his partner Camilla Parker Bowles in April this year.

When the Prince of Wales, 56, becomes king, 57-year-old Camilla will not be known Queen Camilla but as the Princess Consort.

After her marriage she will also carry the title of Duchess of Cornwall, Clarence House, the official residence of Prince Charles, said.

It said the ceremony would take place at Windsor Castle on Friday, April 8 in "a largely private occasion for family and friends" -- without the pomp and circumstance of Charles's wedding to Diana in 1981.

"Mrs Parker Bowles and I are absolutely delighted. It will be a very special day for us and our families," Prince Charles said in a statement.

Charles and Diana divorced in 1996, and Diana had famously revealed in an interview that "there were three people" in their marriage.

In a statement, Queen Elizabeth II said: "The Duke of Edinburgh (Prince Philip) and I are very happy that the Prince of Wales and Mrs Parker Bowles are to marry. We have given them our warmest good wishes for their future together."

The marriage will end years of speculation on their relationship, which has spanned more than three decades.