LONDON (AP) — Queen Elizabeth II is celebrating her official 90th birthday with a three-day series of festivities.

The queen's birthday has been a three-month affair starting with her real birthday in April. The monarch's birthday is traditionally celebrated in June when London's weather can be more favorable.

Elizabeth and her husband Prince Philip will attend a service of thanksgiving at St. Paul's Cathedral Friday on what is Philip's 95th birthday.

The traditional Trooping the Color parade will be held Saturday, the queen's official birthday. The event is expected to draw throngs of Britons and visitors to Buckingham Palace for a possible balcony appearance by the senior royals.

On Sunday, the Mall in front of the palace will host lunch for hundreds of charity workers and members of the royal family.