The Queen has been treated to an impromptu rendition of the song Happy Birthday, following an Easter Mattins service at St George’s Chapel at Windsor Castle.

This year, the monarch’s 93rd birthday coincided with Easter Sunday, the most important day in the Christian calendar.

The Queen – who is head of the Church of England – wore a mint green coat and a matching hat with pink ribbon as she was joined by members of her family at St George’s Chapel.

Following an hour-long service, the Queen was presented with two posies – one yellow and one white – by two little boys, before being treated to the celebratory chorus by crowds gathered outside in the sun.

As the well-wishers completed three cheers, the Queen waved to them as she got into her waiting car.

The Queen is presented with flowers
The Queen is presented with flowers as she leaves the Easter Mattins service (Eamonn McCormack/PA)

Royal family members who attended the service included the Princess Royal, her husband Vice Admiral Sir Timothy Laurence, Zara and Mike Tindall, Princess Beatrice, the Earl of Wessex, the Duke and Duchess of Cambridge, and the Duke of Sussex.

Harry’s heavily-pregnant wife Meghan was absent, as was the Duke of Edinburgh who has retired from royal duties.

Both Harry and Meghan were also among those wishing her well, writing on Instagram: “Happy Birthday Your Majesty, Ma’am, Granny. Wishing you the most wonderful day! Harry & Meghan.”

Anne’s son Peter Phillips and his wife Autumn, and Edward’s wife the Countess of Wessex and their children Lady Louise Windsor and James, Viscount Severn, were also in attendance at the chapel.

Ahead of the service, as the Queen walked into the 14th-century Gothic chapel, Kate, who was wearing a light blue coat, curtsied to the monarch along with other female members of the family, as the males bowed their heads.

Easter service at Windsor
The Duke and Duchess of Cambridge greet the Queen (Kirsty Wigglesworth/PA)

Harry could also be seen chatting away to his cousin Ms Tindall, but appeared not to speak to his brother amid rumours of a possible rift between the pair.

April 21 – the day the Queen was born – is the first of the monarch’s two birthdays. She also has an official one on the second Saturday in June each year, which is commemorated with the Trooping the Colour parade.

Gun salutes are also fired as a mark of respect to the Queen on her special day – but never on a Sunday, so this year they will be delayed by one day.

Longest-living British royals
(PA Graphics)

At Buckingham Palace, the Band of the Irish Guards will also perform a rendition of Happy Birthday in her honour on the forecourt as part of the Changing of the Guard ceremony.

The Queen traditionally spends a month-long residence at Windsor Castle, known as Easter Court, each year.

Princess Elizabeth Alexandra Mary was born at 2.40am on April 21 1926, the first child of the then Duke and Duchess of York, at 17 Bruton Street, the Mayfair home of her mother’s parents, the Earl and Countess of Strathmore.

She was never expected to be Queen when she was born, but the abdication of her uncle Edward VIII in 1936 put her father George VI on the throne, and changed her destiny.

Elizabeth II, who has been monarch for more than 67 years, is Head of State, the Armed Forces and the Commonwealth, and has been married to the Duke of Edinburgh for more than 71 years.

She became Britain’s longest-reigning monarch, passing her great-great grandmother Queen Victoria’s record, in September 2015.

With the death of 88-year-old King Bhumibol Adulyadej of Thailand in 2016, the Queen now holds the record for the world’s longest reigning living monarch.