Heir to UK throne for 60 years, Prince Charles celebrates his 70th birthday

London: Britain's Prince Charles, who has been heir to the throne for more than six decades, celebrates his 70th birthday with a tea party and a banquet in Buckingham Palace on Wednesday.

In two official photographs released to mark the Prince of Wales's milestone, Charles is shown surrounded by his wife Camilla, two sons William and Harry and three grandchildren.

A fourth grandchild is on the way after Prince Harry's wife Meghan, an American former TV actress, announced her pregnancy following the couple's Windsor Castle wedding this year. Charles is set to attend a tea party later on Wednesday with "inspirational people" who are also turning 70 this year.

In the evening, Queen Elizabeth II is holding a banquet which friends, family and European royals are expected to attend.

There will be gun salutes in London and lawmakers will voice their congratulations for the king-in-waiting in parliament. The Twitter account for Clarence House, Charles's official residence, featured flying balloons and a slideshow of pictures from throughout the prince's life to mark the occasion.

Charles also edited an edition of Country Life to mark his birthday. The prince told the magazine about his fondness for red pheasant crumble pie and "groussaka" -- a version of the Greek dish moussaka but with grouse instead of lamb.

He also said he allowed red squirrels, which are being pushed out by American grey squirrels in Britain, to run around his home on the Queen's Balmoral estate in Scotland.