The Queen is celebrating her 96th birthday at Sandringham, where she will be joined by family and friends.
A photograph showing the Queen with two ponies has been released to commemorate the occasion.
The image was taken at Windsor Castle, where the Queen now mostly spends her time.
Britain’s longest-serving Monarch is this year marking her 70th year on the throne.
Birthday wishes have been sent to her from Prime Minister Boris Johnson and Labour leader Sir Keir Starmer.
Gun salutes will be also fired in her honour on Thursday.
And Mattel, the company behind the Barbie doll, have revealed an honorary doll in her image.
The Queen Elizabeth II Barbie is fitted with an elegant ivory gown and blue ribbon adorned with decorations of order.
It will also feature a tiara modelled on Queen Mary’s fringe tiara, which the Queen wore on her own wedding day.
The doll will be sold at Harrods, Hamley’s, Selfridges, John Lewis and on Amazon.
Earlier this week, the Duke of Sussex spoke positively about his meeting with the Queen, having spent two years away from the UK.
In an interview with NBC’s Today show, Harry also said that he wanted to make sure his grandmother was “protected” and had “the right people around her”.
He said “Being with her it was great, it was just so nice to see her, she’s on great form.
“She’s always got a great sense of humour with me and I’m just making sure that she’s protected and got the right people around her.”
The Queen has had issues with her mobility in recent months and has missed a number of events.
It included the annual Easter Sunday service at St George’s Chapel in Windsor.
She also overcame a bout of Covid and has spoken about how the virus left her feeling ‘exhausted’.