Princess Diana was beloved by the public for many reasons, including her warmth, her beauty, and her passion for helping others. But she was also the subject of constant tabloid speculation, as the press tracked her every move. A never-ending subject of fascination was the men in her life. While Diana rose to fame as the wife of Princes Charles, her life came to an end seated in the back of a Mercedes beside Dodi Al-Fayed, a playboy who by some accounts Diana was ready to wed, and by others, was nothing more to the princess than a summer fling.

But somewhere in between relationships with these two high-profile men, Diana fell for someone else that friends believed to be the one true love of her life: Hasnat Khan, a Pakistani heart surgeon with whom the princess had a two-year on-again, off-again romance.

As the 20-year anniversary of Diana’s untimely death approaches, here’s what you need to know about the man Diana famously called “Mr. Wonderful.”

1. He met Diana at work

Though Diana spent much of her life doing charity work, her reason for being at London’s Royal Brompton Hospital one September day in 1995 was personal: She was visiting the husband of a friend who was recovering from heart surgery, according to the Telegraph. Hasnat Khan had assisted in the tripe-bypass surgery, according to Vanity Fair, and Diana was instantly attracted to him physically. “Isn’t he drop-dead gorgeous?” the friend, Oonagh Toffolo, recalled her saying. The princess then returned to the hospital following that first visit “almost every day for three weeks to pursue Khan,” reported the Guardian.

2. Diana saw something special in him.

While Khan’s career was impressive, he wasn’t exactly the type of man you’d expect one of the most famous women in the world to go for. Diana’s butler Paul Burrell put it bluntly in the ABC News special The Last 100 Days of Diana: “He’s the most unlikely character to be a lover for the princess. He’s not sporty, he’s not handsome, he’s not wealthy. So what is it?”

As one friend of Diana’s told Vanity Fair, “When you think of the kind of men Diana must have met or been with or seen — here is a man who is completely and totally selfless. She said she’d never met anybody like him.”

Indeed, after years in the public eye, Diana seemed to crave normalcy. Khan recalled to police that once when the couple was out at a pub, Diana wanted to order the drinks because it was something she’d never had the chance to do before.

Khan has always been tight-lipped about the emotional aspects of their relationship, offering only sterile compliments such as that she was “very down to earth and she made everyone feel at ease.” But as for Diana’s feelings, Burrell has said Khan was “the true love of her life.”

3. Their love affair started out top secret.

When calling the hospital, Diana would leave messages for Khan using the name “Dr. Armani,” according to the Guardian, and when going out with Khan, Diana sometimes went so far as to disguise herself with a black wig and dark sunglasses.

In the book The Diana Chronicles, Tina Brown even wrote that “Khan, hidden under a blanket in Paul Burrell’s car, would arrive at Kensington Palace with Kentucky Fried Chicken for dinner a deux with the princess.”

So why all the secrecy? For one thing, Diana was hounded by paparazzi at every turn, and that was not a world Khan wanted to be a part of. “I told her that the only way I could see us having a vaguely normal life together would be if we went to Pakistan, as the press don’t bother you there,” Khan revealed in the inquest into Diana’s death. “I did not want to have to look over my shoulder all the time.”

4. He and Diana couldn’t make it work

Jemima Khan, a friend of Diana’s and wife of Hasnat’s distant cousin, told Vanity Fairthat Diana was “madly in love” with Hasnat Khan and “wanted to marry him, even if that meant living in Pakistan.” But despite trips to Pakistan to woo Khan’s strict Muslim mother, Diana could not move the relationship forward.

“I think Hasnat was very much in love with Diana, but had really reached the end of his tether because Diana pushed him and pushed him and pushed him to go public and say we’re a couple, and he wouldn’t,” Tina Brown said in The Last 100 Days of Diana. “So she gave him an ultimatum, either we go public or this isn’t going to happen.”
It didn’t happen. “Even after two years, the relationship wasn’t leading to a meaningful progression or conclusion and that was the main stress on both of us,” Khan told the Daily Mail.
5. Diana may have tried to make Khan jealous.

In the final summer of her life, Diana caused a stir when she was photographed aboard a yacht embracing Dodi Al-Fayed, the son of Egyptian billionaire Mohamed Al-Fayed, who was then the owner of the famed department store Harrods. Author Sally Bedell Smith wrote in her book, Diana in Search of Herself, that Diana’s friends revealed the photographs were a message “meant for one reader, Hasnat Khan,” according to Vanity Fair.

Messaged received. Years later, Khan would reveal that he had heard about Diana’s relationship with Fayed on the radio. “I think she wanted to be with someone who was happy to be seen with her in public and she could do that with Dodi,” Khan said, adding, “I think that Diana finally realized that Al-Fayed could give her all the things I could not.”

6. He tried to call Diana the night she died

Richard Kay, a friend of Diana’s, said in The Last 100 Days of Diana that Khan attempted to reach her that night, but was unable to get through. “I think he was worried about her,” said Kay. “I think he was worried, as were a lot of her friends, about what she’d got herself into.”

Khan revealed as much in a conversation with Kay: “He said to me, ‘Maybe later in the summer, we’d have got back together again.'”

In the special, Diana’s butler Paul Burrell speculates as to what Khan would’ve said to Diana that fateful night: “I think Hasnat’s last call would’ve been, ‘Isn’t it about time you came home to me? Because I miss you.'”

7. He’s since moved on

In 2006, Khan wed Hadia Sher Ali in an arranged marriage with a “lavish ceremony” in Pakistan, according to the Telegraph. Just 18 months later, the couple split. Now 58, he’s currently listed as a consultant cardiac surgeon at Basildon and Thurrock University Hospitals in England.

8. Diana and Khan’s relationship was immortalized in a 2013 film

Naomi Watts starred as the title character in Diana, while Khan was portrayed by Naveen Andrews, best known for his role as Sayid on the hit ABC series Lost. The film homes in on the final two years of Diana’s life, featuring her romance with Khan.

Prior to the movie’s release, Khan slammed it in an interview with the Daily Mail. “It is based on gossip and Diana’s friends talking about a relationship that they didn’t know much about, and some of my relatives who didn’t know much about it either,” he said, adding, “There wasn’t any hierarchy in our relationship. She wasn’t a Princess and I wasn’t a doctor.”

Critics didn’t like the movie any more than he did – Diana stands with a dismal 8% rating on Rotten Tomatoes.

By Good Housekeeping