The brothers, whose falling out has been the subject of intense media focus, displayed a united front as they revealed the statue they commissioned in honour of Diana in the Sunken Garden of Kensington Palace in central London, her former home.
Diana was killed in a Paris car crash in 1997.
“Today, on what would have been our Mother’s 60th birthday, we remember her love, strength and character – qualities that made her a force for good around the world, changing countless lives for the better,” the brothers said in a statement.
“Every day, we wish she were still with us, and our hope is that this statue will be seen forever as a symbol of her life and her legacy.”
William, 39, and Harry, 36, were joined by their mother`s brother Charles Spencer and her sisters Sarah McCorquodale and Jane Fellowes for the small, private event at the Sunken Garden, one of Diana`s favourite places.