Cary Elwes in “The Princess Bride.”

He may be most known for a single, legendary role in cult-favorite film The Princess Bride, but Cary Elwes is not just an actor. He’s now a best-selling author and more recently, a screenwriter.

“I have a movie that I wrote that’s being shot right now being made into a film. It’s about the meeting of Elvis and Nixon,” said Elwes, who will be in San Francisco Monday as a special guest for a “Quote-Along” screening of The Princess Bride at SF Sketchfest at the Castro Theatre.

The film stars Kevin Spacey as Nixon and Michael Shannon as Elvis, and examines their meeting at the White House in 1970. Why did Elwes focus on the story of this summit?

“Because it’s so unbelievable. The more I delved into the facts, I realized I didn’t need to embellish much to make it a comedy.”

Elwes is a fan of music. The Who has been his favorite band since his teens, and he is a fan of Pete Townsend’s songwriting. He also listens to Thenewno2, which is led by Dhani Harrison, the son of former Beatle George. And Elwes is fond of reggae and world music artists such as Bob Marley, Linton Kwesi Johnson, UB40, and King Sunny Ade.

And then there’s Elvis Presley, at the center of his new film.

“You can’t be a music fan and not be (a fan of Elvis),” he said. “I mean, even John Lennon said there’d be no Beatles without Elvis.”

The 52-year-old Elwes has had multiple starring roles: As Robin Hood in Mel Brooks’ comedy Robin Hood: Men in Tights, alongside Tom Cruise in Days of Thunder, and the Academy Award-winning Glory. Fans of the Saw series may not know that it was not his first turn in the horror genre. That would be Francis Coppola’s adaptation of Bram Stoker’s Dracula. There are many other roles in film alone, not counting popular turns on television, such as Psych and The X-Files (his two favorite TV roles).

Cary Elwes, courtesy: Penn Turin.

Yet his most famous role is his turn as Westley/Dread Pirate Roberts in Rob Reiner’s The Princess Bride, based on the 1973 novel of the same name by William Goldman. It was Elwes’ step-father who first introduced him to the story of Princess Buttercup, the Dread Pirate Roberts, Inigo Montoya, Fezzik the Giant, Miracle Max and Prince Humperdink, by giving him the book when he was 13.

“It was one of the great reading experiences I had and my long love affair with the work of William Goldman,” he said. Auditioning for the role of Westley brought many of his childhood memories back. “I was very well aware of Rob Reiner. I’d seen (This Is) Spinal Tap quite a few times, as I’m sure most of your readers have. It was a big role for me; an important role.”

The 1987 film starred Elwes, Mandy Patinkin, Christopher Guest, Billy Crystal, Carol Kane, Chris Sarandon, playwright Wallace Shawn, wrestler Andre The Giant, and Robin Wright (in her first major role). Yet it flopped at the box office. The often-told tale goes that the studio had no idea how to market the film, eventually deciding to put minor narrator characters Fred Savage and Peter Falk on the poster.

It was not until its release on VHS that The Princess Bride began to build its cult following. The fantasy-comedy-romance-action and adventure story is now near and dear to the hearts of many.

“(That is) because it’s all of those things,” Elwes said. “It has everything. And it’s a family movie. Whole families watch it together, and they all enjoy it for different reasons.”

Making the film inspired Elwes to write a book about the experience, with contributions from his costars. “As You Wish: Inconceivable Tales from the Making of The Princess Bride,” released last fall, became a New York Times bestseller.

Elwes shrugs off the best-selling writer status; his book incredulously was more successful than the initial release of the film about which it was written.

“The film has now reached a status that filmmakers only dream of,” he said. “The film is still so popular and so beloved that I wanted the book to be a love letter to the fans, to thank them.”

The film’s memorable quotes helped turn The Princess Bride into a delayed instant classic. “As you wish.” “Hello. My name is Inigo Montoya. You killed my father. Prepare to die.” “Inconceivable!” “Have fun storming the castle!” “To the pain!”

And the plot points that mark Westley’s journey help fans keep pace: The six-fingered man, the Rodents of Unusual Size, the Pit of Despair… All of these lend the story to a quote-along, which Elwes described as a wonderful mawage between the film and the comedy festival.

At the Quote-Along, fans are encouraged to yell out all of the lines they know. A question and answer session will follow the screening.

“Most diehard Princess Bride fans know almost every line before the actors have even spoken them,” he said. “Folks show up in costume and bring props and things like that. It’s rather like the Rocky Horror Picture Show screenings they have.”

Elwes, himself, has a more obscure favorite line from the film. It comes from a conversation between Fezzik, Inigo Montoya and Vezzini, in which Fezzik find a rhyming response for everything his cohorts say.

“Anybody want a peanut,” said Andre the Giant, who passed away in 1993, in response to Wallace Shawn’s demand of “No more rhymes now, I mean it.”

“It just tickles me,” Elwes said. “I don’t know why. Maybe (because) it’s Andre.”

Follow editor Roman Gokhman at Twitter.com/RomiTheWriter.