The Queen has traveled to Sandringham, her estate in Norfolk, eastern England, for a private break, Buckingham Palace told CNN.
A portrait released for the occasion shows the monarch between two fallen ponies named Bybeck Nightingale and Bybeck Katie. The photo was taken in the grounds of Windsor Castle in March, according to the royal family’s Twitter account.
William and Catherine, the Duke and Duchess of Cambridge, sent the Queen a birthday message on social media.
“Wishing Her Majesty the Queen a very happy 96th birthday today!” reads the tweet. “An inspiration to so many in the UK, Commonwealth and around the world, it is very special to celebrate this #PlatinumJubilee year.”
Charles, the Prince of Wales, and Camilla, Duchess of Cornwall also sent a birthday message to the Queen.
“Wishing Her Majesty the Queen a very special 96th birthday today as we celebrate her platinum anniversary year,” the couple tweeted.
The platinum jubilee marks seven decades since the Queen’s accession to the throne in 1952, making her both the longest-reigning British monarch and the longest-serving female head of state in history.
To celebrate the unprecedented anniversary, a series of events will be held throughout the UK throughout the year, culminating in a four day national bank holiday weekend from Thursday 2nd June to Sunday 5th June known as the Jubilee Weekend.
Toy manufacturer Mattel has also announced a Barbie doll in the likeness of the monarch to celebrate the anniversary.
The Queen Elizabeth II Barbie wears an ivory dress, blue ribbon and tiara. It goes on sale from Thursday.
The Queen recently revealed that she was “very tired and exhausted” after a recent bout of Covid-19. The monarch tested positive for the virus in February.
However, her grandson Harry, Duke of Sussex said the Queen was “in great shape” when he saw her in mid-April.
“It was just so nice to see her,” he said in an interview with NBC’s Today show, which aired Wednesday.
Before his grandmother turned 96, Harry commented, “After a certain age, birthdays get boring.”
Discussing the relationship he has with the Queen, Harry described it as “really special,” adding, “We talk about things that she can’t talk about with anyone else.”
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CNN’s Max Foster contributed to this report.