Thriller writer Dan Brown, the master of far-fetched plots featuring larger-than-life-villains, has described the Donald Trump presidency as stranger than fiction.

The author of bestsellers such as The Da Vinci Code admitted he was taking a professional risk by speaking out against Trump during an interview with the Guardian.

“I was at the Frankfurt book fair and somebody asked me if I’d thought about writing about Trump,” Brown recalled. “I said, ‘If I wrote The Trump Code, nobody would believe it.’ Reality has surpassed fiction.”

The writer, who has sold 250m books and had his work translated into 56 languages, recently launched an online masterclass for aspiring thriller writers. But Trump and his outlandish cast of characters outdo even the wildest product of his imagination. “In my masterclass, if I said, ‘Hey, you know what, how’s this idea for a character?’, we would have to cut it out because it would make no sense.

“You would say, ‘Nobody acts like that, certainly nobody who could reach this station.’ I think everyone scratches their head and says it’s a dream, right? We’re going to wake up and say, ‘No, the world is the way we thought. It’s not like this.’ I guess we’re not. Well, the world is changing.”

The Trump presidency is reverberating through the literary world. Shelves are already groaning under books written by former White House officials Omarosa Manigault Newman, Anthony Scaramucci and Sean Spicer, as well as ex-FBI director James Comey and journalists Tucker Carlson, Major Garrett, Michael Wolff and Bob Woodward.

“If you talk to people in the book business, it is hard to sell books right now,” Brown said. “Nonfiction is getting killed unless you’re writing politics because the nonfiction world of CNN and Fox or MSNBC or whoever, pick your poison, is so far more entertaining and horrifying.”

Catching himself, the 54-year-old added: “I hope that’s a true statement: I know some people aren’t horrified but I, personally, am pretty horrified. It’s heartbreaking. I spend a lot of time in Europe and I have a lot of friends in Europe who just feel that the reputation of this country as an ally, as a leader in so many things, has been deeply damaged. I understand why allies are going like, ‘Really? Maybe we’ll just do this ourselves.’ It saddens me because I love this country very deeply.”

Brown joins a host of artists, from Robert De Niro to Meryl Streep to Jay-Z, who have denounced Trump. Musician Taylor Swift recently broke a long political silence to endorse Democrats in the midterm elections; the president said he likes her music “about 25% less now”. Even Kanye West, a prominent Trump supporter who paid a bizarre visit to the Oval Office, recently announced he is stepping away from politics.

Brown’s work is filled with clues, secrets and symbols but he admits he missed all the signs of Trump’s victory two years ago. “I have no idea how he got elected. I have lot of friends in the UK who sort of described the same experience we had in the US. You wake up and like, ‘Wait, Brexit happened? I don’t understand. That’s how we were getting up the next morning.”

Brown lives in New Hampshire, an electoral hotbed because of the presidential primaries every four years, but does not regard himself as a political person.

Yet America’s political divide even extends to where people shop and what television they watch. But Brown’s following is so vast that he surely had both pro-Trump conservatives and anti-Trump liberals among his readers. He agreed: “I do. It’s fascinating. You realize you really can’t be political. For me to say I’m not a fan of Trump to you publicly is probably professionally not that smart. But at some point you just say, ‘Well, that’s how I feel.’”

And ultimately, he said, he remains fundamentally optimistic. “I’m not concerned because I deal in long history. I deal in trends that happen over centuries. To somebody else maybe in the financial market you might look at this and look at day by day and say this is a fiasco. If you step back, you see this Trump presidency as a blip on a much longer timeline that will right itself. We’ll figure it out.”