Queen's birthday photo released

Ms Phillips (left), the Queen and Princess Anne are pictured together

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The Queen is having a quiet day at home on Wednesday, her 78th birthday - but the occasion is being marked by the release of a photo of her on horseback.

She was photographed during the Easter Weekend with her daughter Anne, the Princess Royal, 53, and her 22-year-old granddaughter, Zara Phillips.

The Queen is pictured riding her favourite mare, 20-year-old Tinkerbell.

Her official birthday will be celebrated with the annual Trooping the Colour pageant on 12 June.

The three generations of royal horsewomen were captured on film by a Windsor Castle Royal Archive photographer.

The Princess Royal is pictured on Peter Pan, who is seven, while Ms Phillips rides three-year-old Tiger Lily.

The two younger horses are Tinkerbell's son and daughter.