Being the daughter of one of music’s greatest legends, Lisa Marie Presley, allowed her to rub shoulders with celebrities worldwide. Still, the recently deceased daughter of Elvis Presley had an almost secret friendship with one of the most famous people in British royalty that few knew about.

Fergie remembered her with an Instagram message.

Among many other friendships, Lisa Marie had one with the Duchess of York herself, Sarah Ferguson, which few knew about. This was revealed through an Instagram post in which ‘Fergie’ penned a loving tribute to Lisa Marie following her passing.

“I salute you every day, my sister, and I love you, and I will continue to salute you every day,” Fergie, 63, wrote beside a photo of the two.

“You were my sister, an incredible mother to Ben, Riley, Harper, and Finley, and a gloriously devoted daughter to Priscilla. You have been a loyal friend for many years, and I am here to support and adore your family. I am heartbroken, my sister; you are in my thoughts,” she wrote.

According to a source close to Ferguson, Lisa Marie and Sarah met in 2010 while the former was living in Sussex with her ex-husband Michael Lockwood.

“They seemed to get on right away,” the source recalled, adding that they were friends with Bob Geldof, his wife, Jeanne Marine, Jeff Beck, and his wife, Sandra.

“They became good friends and stayed in touch after Lisa Marie returned to the United States. And she was quite supportive of the duchess during difficult times, particularly when embroiled in the ‘false sheik’ affair.”

In addition, Lisa Marie offered “a refuge” in Hawaii to Fergie when she fell on hard times, and “the Duchess never forgot that Lisa Marie went out of her way to be a helpful friend.” They truly bonded as sisters.

The two were so close that they discussed [Lisa Marie’s] daughter Riley working alongside the Duchess on cinematic projects since her first adult novel was being developed into a TV series or movie a few weeks ago.

Rest in peace, Lisa.