Princess Diana died on August 31, 1997 in a tragic vehicle accident that took place in Paris.
As part of Take That, Barlow performed at the Concert for Diana benefit event at Wembley in 2007, alongside global stars including Elton John and Kanye West.
The Italian choreographer and dancer, 63, said: "22 years today..." The Take That singer reminisced about meeting the royal while commemorating the 22nd anniversary of her death.
During a segment on ABC's Good Morning America, she claimed William said his son "absolutely loves ballet".
U.S. actress Jamie Lee Curtis recalled how she had missed meeting Diana when the princess visited the famous Pinewood Studios, where she was shooting the 1988 film A Fish Called Wanda.
Nearly 22 years have passed since Diana's death, which shocked the world, but her appeal remains undiminished.
"So, I do, [when] regularly putting George or Charlotte to bed, talk about her and just try and remind them that there are two grandmothers, there were two grandmothers in their lives".
She also revealed: "I think Granny is the most happy there".
United in grief, the princes have reportedly grown distant from each other this year amid reports of a rift that saw Harry and his wife Meghan move away from their home in Kensington Palace near William and Kate and into Frogmore Cottage at Windsor 34km away.
When it comes to commemorating the anniversary of her death, the future king will likely spend some solo time with his younger brother, as they've been known to do in years past, eating lunch or dinner together at Kensington Palace while sharing memories of their late mom. Victoria Murphy, a royal commentator, wrote in the "Town & Country" magazine: "Four years later, Meghan has found herself at the helm of one of the most high-profile households in the world's most famous royal family".