The image, which was taken in March on the grounds of Windsor Castle by Henry Dallal, depicts the monarch standing between two of her white Fell ponies, named Bybeck Nightingale and Bybeck Katie.
The ponies stand taller than the queen, who is holding them both by the reins in the image.
Queen Elizabeth's long-time love for horses is no secret. She was given her first pony aged 4, a gift from her grandfather, King George V. As a child, when she was still known as Princess Elizabeth and had no idea that a future as monarch lay ahead, when asked what she'd like to be when she grows up, in a 1945 edition of Life magazine, she's quoted as replying, "I should like to be a horse."
She is a keen rider, owner and breeder, and a regular at British horse racing events including Royal Ascot, the Epsom Derby and the Grand National.
Click through the gallery above to see photos of Queen Elizabeth and her horses through the years.
“I think this is her passion in life, and she loves it and you can tell how much she loves it,” Camilla, Duchess of Cornwall, said of her mother-in-law during an interview with ITV Racing in June 2021.
“She can tell you every horse she’s bred and owned, from the very beginning, she doesn’t forget anything. I can hardly remember what I bred a year ago, so she’s encyclopedic about her knowledge.”
In 2013 the queen became the first reigning British monarch to win the Royal Ascot Gold Cup, winning with her horse Estimate.
Speaking about the royal, jockey Willies Carson, who has ridden her horses, told ITV: “She's very sharp. We've got to know the Queen quite well, and it's her passion. I wouldn't call it her life, but it's her passion, her hobby, and she really enjoys doing it.
“It's not just the horse racing she enjoys, she enjoys the breeding side of it. She likes to know from trainers how the horse is behaving and its attitude, its temperament. She wants to know those things. That's what she's really interested in," he said. "The winning post is the end result and she enjoys that, of course, but she enjoys everything before you get to the winning post. That gives her the most pleasure."