When Stephen King got the call to come back to Derry, he reacted like a typical Loser—resistant at first, trying to bargain his way out of the idea. But finally he accepted that it was the right thing to do.

That’s how the father of Pennywise the Dancing Clown turned up in a scene-stealing role as a grumpy shopkeeper in It: Chapter Two. And now that the film has opened to $185 million at the global box office, King is telling the story of his involvement in the sequel, including his thoughts on one of the major additions it made to his original 1986 novel.

King, who turns 72 later this month, didn’t appear in 2017’s It; he has little interest in rivaling Stan Lee or Alfred Hitchcock’s litany of creator cameos, having significantly cut back on his screen appearances over the years. He prefers to focus on writing, and has a new book, The Institute—about psychic children who are forcibly rounded up by a sinister organization—hitting stores on Tuesday.

The author was lured to the It: Chapter Two set last year by two things: director Andy Muschietti’s concept for the cameo, a timeline-jumping idea that was ultimately abandoned, and the opportunity to be a total jerk to best-selling writer Bill Denbrough, played by James McAvoy—hitting him with some of the drive-by negging King himself has endured from armchair critics over the years.

“Yep,” King told Vanity Fair with a laugh. “It was a huge pleasure to do that.”

In the film, King plays the bespectacled proprietor of Secondhand Rose, a consignment store where Denbrough discovers the rust-flecked remains of Silver, his beloved childhood bicycle. The shopkeeper instantly recognizes Denbrough as a popular author, knows he has a lot of money, and intends to get as much of it as possible for that beat-up old bike. Sentimental value can have a steep price.

When Denbrough offers to conclude the transaction by autographing one of his books, the shopkeeper not-so-politely snaps that he doesn’t care for Denbrough’s endings. (Shots like those really do irk King, even to this day.)

But apparently this is not the first time the Secondhand Rose owner has crossed paths with Denbrough. Muschietti confirmed that originally, the film planned to have King’s shopkeeper show up in a flashback, interacting with young Bill (played by Jaeden Martell) and his friend Beverly Marsh (played by Sophia Lillis).

“When Bill Denbrough walked into the thrift shop, he had a flashback of him and Beverly browsing the same place 27 years ago,” Muschietti said. “It was a little romantic moment there, and then they were approached by the shopkeeper as a younger version.”

There would have been no digital de-aging for King, however. Instead, the younger shopkeeper who ruins their tender moment would have been played by King’s son, author Joe Hill.

“Andy’s original idea was so genius,” King said. “He wanted to use Joe as that guy in a flashback with the kid, and it would’ve worked because Joe and I look a lot alike.”

Alas, the idea was never shot. “We started with a script that was 160 pages, and that was the short version,” Muschietti said. “Unfortunately, we had to shave it off. It was impossible.”

But the author remained committed to the cameo, despite his early qualms. “Andy asked me if I’d do that, and the major thing for me is: How hard is it going to be to get there?” said King, who doesn’t like to travel often. Fortunately It: Chapter Two was filming just over the border from Maine—and curiosity from another generation also led King to participate: “They were shooting in Port Hope in Canada, and it was really just a hop. So I went up with my grandson, who’s crazy about movies—the oldest one, Ethan—and we hung out on the set. It was cool.”