In 1981, a newly engaged Diana Spencer appeared at a London fundraiser in a black strapless Emanuel gown “two sizes too small.” Blinded by flashbulbs and feeling short of breath in the tight dress, the 19-year-old thought she might pass out.

“I was terrified, really — at the time everything was all over the place,” Diana told her biographer. Grace Kelly, aka Monaco’s Princess Grace, noticed the young woman’s discomfort and suggested they retire to the ladies’ lounge together.

In private, Diana burst into tears as Grace offered understanding and humor. “Don’t worry, dear,” she joked as she patted Diana’s cheek. “It will only get worse.”

Of course, Grace was right. Privately, the elder princess was worried for Diana. “They have nothing in common,” Grace said of Diana and Prince Charles, according to True Grace author Wendy Leigh. “I think he’s far too old for her, and she’s very, very young herself.”

But the actress-turned-royal, whose husband, Prince Rainier, was a distant relative of Charles’, would attend the couple’s elaborate royal wedding.

When Grace died in a car accident in 1982, Diana felt the need to pay her respects in person. “It’s important because she was an outsider who married into a big family, and I’ve done the same, so it would feel right,” she told Charles, who insisted her attendance was unnecessary.

Undeterred, Diana appealed to Queen Elizabeth, who agreed to allow her to go to Monaco. It meant more to Diana than anyone realized. She told Grace’s daughter Princess Caroline that she felt “psychically connected” to Grace and would always treasure her kindness.