Kevin Costner was treated to a royal surprise in a conversation with Prince William “some years back,” he told People: The late Princess Diana had a thing for him.

In a new interview with the magazine, published Tuesday, the Yellowstone actor revealed that William had once asked to meet with him while he was in England.

“We met in this room, and it was just us,” Costner said. “He walked up, and we shook hands... The first line out of his mouth was, ‘You know, my mom kind of fancied you.’”

He didn’t share what else they talked about, though Costner called the now-Prince of Wales “quite a young man” and said their meeting was “very sweet.”

Costner was in touch with Diana before her 1997 death because they had been in talks about working together on a sequel to his 1992 movie The Bodyguard. Costner would reprise his role as the titular protector, with the People’s Princess as a costar. In real life, the two were first introduced by Sarah Ferguson, the Duchess of York, whom Costner called “very cool.”

“It was so sweet,” Costner said of the intro, and praised Ferguson for not trying to insert herself into the project. “When she could have been going, ‘Well, I’m a princess too. What about me?’ She didn’t do that at all. Diana and I began to talk.”

The film ultimately was not made, of course, but according to Costner, “there was a moment that that was really flying down the tracks, very quietly, because it's how I operate.”

Costner also gave an interview to Howard Stern on Tuesday on his radio show where he went into more depth about what the sequel’s plot would have been and how Diana got involved.

When they first spoke, he said, “She goes, ‘My life’s about to change.’ I didn’t really go into depth with it, but I thought I understood what she’s saying.” He implied that the conversation had happened shortly before her 1996 divorce from King Charles III, who at the time held the title of Prince of Wales.

In further conversations, they got more into the plot.

“The second time we talked she said, ‘Is there going to be a kissing scene?’ And I said, ‘Do you want there to be one?’ And she said yeah, and I said then we’ll do that.”

Costner said that the plan for the movie’s opening had been to see his character whispering some “really sexy shit” to an unseen subject at a horse race in Hong Kong. “All of a sudden you pull back and you realize I’m talking to a horse.” Twist! His protectee in the movie, he said, was the racehorse, not Princess Diana.

“I wasn’t going to make the full romance about her,” Costner said of the late princess. “It was going to be about this Asian woman, but there was going to be a moment when we did. And she was so sweet about this. I said, ‘I’m going to send you this movie and I’m going to make it, just like Whitney, I’m going to make it so you don’t have to do all that much, but you’re going to be great.’ And she said, ‘I’d like that.’ And then we lost her and she was gone.”

The saga didn’t end with Diana’s death. According to Costner, things got tense with The Firm.

“When Diana passed about a year later, it leaked out that I had been prepping Bodyguard 2 with her,” he said. “What happened was the royal family kind of turned on me a little bit and was like, ‘No, that’s not true.’ It got actually kinda ugly. I let it go for a little while but it just got uglier and uglier. Finally I called up Sarah and I said, ‘Sarah, you need to tell me who’s leading the charge on this thing.’”

Despite Ferguson insisting, according to him, that he really didn’t want to talk to them, he persisted.

“I called them up and I said, ‘I’m telling you something, you need to stop, because it is true. And if you don’t stop, I’m going to start,’ because it was true.”

Representatives for Kevin Costner did not immediately respond to Vanity Fair’s request for comment.