LONDON (Reuters) - Britain’s Queen Elizabeth, the world’s oldest and longest reigning living monarch, celebrated her 93rd birthday on Sunday by attending the traditional Easter service at Windsor Castle.

Elizabeth was accompanied by members of her family, including grandsons Prince William and Prince Harry, and William’s wife Catherine, at the Easter Mattins service in St George’s Chapel.

Prince Harry’s wife Meghan Markle, who is due to give birth to the couple’s first child imminently, did not attend.

The couple, who were married at the chapel in May 2018, posted a birthday greeting to Elizabeth on their official Instagram account.

“Happy Birthday Your Majesty, Ma’am, Granny. Wishing you the most wonderful day! Harry & Meghan,” they wrote.

Elizabeth was born on April 21, 1926, in Bruton Street, central London and became queen in 1952 at the age of 25, meaning she has now reigned for more than 67 years.

She has an official birthday in June which is publicly marked with a large parade of soldiers through central London, known as Trooping the Colour.