The Queen will celebrate her 96th birthday on Thursday in Sandringham, the BBC reports.
Britain’s longest-lived monarch travelled by helicopter to her Norfolk estate, where she will be joined by family and friends.
She is expected to stay in a cottage on the estate particularly liked by her late husband, Prince Philip.
A photograph has been released to mark the birthday, showing the Queen with two ponies and reflecting her lifelong interest in horses.
The picture was taken at Windsor Castle, where the Queen now mostly stays, and shows her with two Fell ponies, who will appear in the forthcoming Royal Windsor Horse Show.