I pity Jeff Kinney's sons. It's hard enough growing up, without worrying that your merest indiscretion might get immortalised in one of the world's best-selling books, especially when said work mocks the exploits of one Greg Heffley, aka the Wimpy Kid.
Such is the peril of having a father who earns his living poking fun at the everyday angst of a boy approaching adolescence, not that the dad in question seems the least bit perturbed.
"It's funny you should ask," he says in his monotone American twang, inviting me to laugh at a story involving his oldest child, a "mock spank", the annual White House Easter Egg Roll and an audience of some 30,000 people.
The sons – aged 10 and 7 – were sitting next to Kinney, 41, during a book reading on the famous lawn. He'd charged them to behave, and thought they'd pulled it off, but a video clip on the White House website suggests otherwise.
"My younger son bends over to look at the book on my lap and my older son seizes the opportunity and mock spanks him. My son is embarrassed when I talk about it but I say, 'Hey, you did it for the public. You have to live with it.'"
The mind boggles at what else the 10-year-old Will might have to live with now that he's approaching the same age as his father's notorious pen-and-ink creation. In the latest instalment of Greg's escapades, Diary of a Wimpy Kid: The Third Wheel – which outsold every other book in the UK in the first two weeks it was published – chicken pox, pimples and an inability to score a date for the school dance are just a few of the plights that befall Kinney's anti-hero.
Cringe-worthy stuff but hugely popular: a total of more than 75 million Wimpy Kid books have been sold in more than 44 countries around the world and UK sales top 10 million. Children can't get enough of Heffley's adventures or, rather his misadventures, which generally invite ridicule. The hapless middle child cuts a gauche line between his tougher older brother, Rodrick, and his spoiled younger sibling, Manny, against the backdrop of that trickiest of pre-teenage breeding grounds, the American middle school.
Kinney says his own middle-school years "felt like quarantine", adding: "Most people in America would say that if you missed out those years before High School you wouldn't be missing much." He reckons his eldest will survive by virtue of being quite tall. "He won't be the small kid in the hallway."
It's all been rather a shock for the unassuming web developer, who looks like he was born to live in Plainville, his hometown in Massachusetts, and admits that he only invented the childish-looking character because his drawing style wasn't good enough for him to forge a career as a newspaper cartoonist.
His early work appeared back in 2004 on the educational gaming website where he still works, FunBrain, in the form of short, daily entries from Greg Heffley's diary. It was an instant hit, and a book deal followed three years later. "I did the drawings at the maximum age level that I felt I could credibly draw," Kinney recalls. Five years on, he finds "every moment surreal," gesturing at the floor-to-ceiling windows overlooking the Thames on the 10th floor at the headquarters of his UK publisher, Puffin, where we meet.
"Looking over London with a view to die for is strange and surreal; meeting three presidents is strange; speaking at the Sydney Opera House; at Davos." He is milking his time in the sun, which includes overseeing three blockbuster movie spin-offs, which have made £125m globally. He snaps the chilly scene below him with his iPhone, just before answering questions for a Blue Peter film crew that is following for the day.
Later, he flicks through his shots for my benefit, pausing at the one of him and the Obamas taken after that book reading. That's all the Obamas, down to their dog Bo, and all the Kinneys, including his mum and dad.
"The famous dog was what we had in common," he tells me: like America's first family, the Kinneys own a Portuguese Water Dog, Thunder. "It's a political statement," he deadpans.
Other snaps include one of Kinney, who is on a fleeting UK book tour, pretending to push a luggage trolley through Platform 9 ¾ at King's Cross station in homage to that other fictional marvel, Harry Potter. In fact, it should arguably be JK Rowling heaping the praise on Greg Heffley: Blue Peter viewers recently voted Diary of a Wimpy Kid the best children's book of the past decade, trouncing the boy wizard.
Where Kinney perhaps retains the edge is that the Wimpy Kid will never age, forever freezing him in children's affections. "The character's DNA is in cartoons, and the best cartoon characters don't grow old. There's a suspension of disbelief, so I've decided to keep him the same age forever."
This means Kinney, who works on his creation in his spare time in the house next door to his family home, which he bought with his Wimpy Kid spoils, could keep on churning out Greg's adventures. He says he has at least three more instalments in him, adding to seven already published.
It's obvious his books get children turning pages: those sales stats speak for themselves. This explains why Time magazine named Kinney in its 2009 top 100 influential people poll, much to the writer's amazement.
"I thought it was a joke. If I do have any real influence, it's that kids who pick up my books learn that reading can be fun and rewarding. If you give a kid a book or magazine that speaks to their interests I think you have the best shot of turning them into readers. One reason my books are popular is because they are filled with humour and kids don't think of them as work," he says.
I'm most intrigued by his notion that wimpy kids today have a lot more going for them than when Kinney was young. "In the past 10 years, we've been celebrating all types of people in the world. Even being a geek is cool: there's geek chic," he says. I'm doubtful this extends to spotty wannabe adolescents but Kinney is adamant. "There's a lot more acceptance and understanding in some ways than there used to be. You don't see these overbearing masculine dads trying to turn their wimpy kids into athletic types. I see more understanding for kids that are different and who march to the beat of their own drum," he adds.
Kinney himself ploughs his own furrow, with his text-and-cartoon books straddling the worlds of novels and comics. "I don't feel like a real writer, and I don't feel like a comic artist either." Wherever he sits, his work couldn't be more in vogue given the recent decision to shortlist two graphic works for the Costa book awards.
His sons had better watch out: given the sort of success their father is enjoying, one more false move, especially one recorded for posterity on a YouTube clip, could see the entire world laughing at them.
1971 Born on an air force base in Maryland, USA, he grows up in a suburb of Washington DC. He has a "very normal, very typical" American childhood as one of four siblings (two brothers, one sister). His father worked for the government at the Pentagon, and his mother was an educator.
1990 While studying at the University of Maryland, he creates his first popular comic strip, Igdoof, which ran in the campus newspaper, The Diamondback. Kinney flirts with the notion of becoming a newspaper cartoonist.
1997 Marries Julie. They have two children, Will, and Grant, and live in Plainville, Massachusetts.
2004 By now, Kinney is working on the website FunBrain, where he publishes an online version of Diary of a Wimpy Kid, which becomes an instant hit and leads to his first book deal.
2007 The first instalment of Greg Heffley's life is published, Diary of a Wimpy Kid, with an initial print run of just 15,000. The book's instant success surprised everyone, not least Kinney.
2009 Time magazine names him one of the year's 100 most influential people. He speaks at the World Economic Forum, in Davos. One year later, the first Wimpy Kid film is released.
2012 Kinney publishes his seventh Wimpy Kid book and has a cameo role in the third film, Diary of a Wimpy Kid: Dog Days, which has just come out on DVD.