DESPITE writing and directing American Pie: Reunion, the latest in the hit series of comedies, Jon Hurwitz and Hayden Schlossberg haven't attended their own high school trips down memory lane, good and bad.

The nearest these New Jersey boys have come are the weddings of friends and schoolmates. So, does everyone at these occasions hate them because they are now hotshot Hollywood types?

"Not to our face," says Hurwitz, laughing. "Everyone acts really proud of us and supportive of our movies. I'm sure there's probably somebody out there who can't stand us and curses us every day but we've been lucky enough to see a lot of love from the people of our home town."

Having created the low budget, mega-earning Harold & Kumar comedy franchise – Harold & Kumar Get the Munchies, Harold & Kumar Escape from Guantanamo Bay, and A Very Harold & Kumar 3D Christmas – the duo were handed the keys to American Pie: Reunion. The first American Pie, released in 1999, made £146 million worldwide, the last before Reunion, American Wedding, grossed £143m.

For Hurwitz and Schlossberg, devotees of the original movie and subsequent ones, it was fan fantasy time when Universal called.

"Watching American Pie was like watching us and our friends on the screen," says Schlossberg, 33.

The original Paul and Chris Weitz film, written by Adam Herz, was unlike anything else around at the time, says Hurwitz. Studios, worried they would lose out on their target audience with a higher rating, were making nothing but tame high school movies.

"That led to characters that didn't really swear, sexual subjects were taboo," says Schlossberg. "When we were in high school that was not at all what our high school experience was like. It didn't feel authentic to us."

The two started to write their own high school comedy. Part way through, they saw a trailer for American Pie. They had been beaten to the punch, but at least they knew they were in synch with what the industry wanted.

When they took on Reunion they weren't told to go in any direction, says Schlossberg. "As fans, we thought what would we like to see. On the one hand we didn't want to change too much because we wouldn't want to see something different ... But at the same time what was important to us was that people in their 30s could relate to these characters, the way teenagers were able to relate to them when they were teenagers."

So Reunion, for example, features a married couple whose sex life is not what it used to be, and a party animal who hasn't learned that the party's over.

The Pie series, like Harold and Kumar, is what might be termed OMG comedy, as in "Oh my God, I can't believe I'm seeing/hearing this." See infamous apple pie incident in American Pie for more details.

In writing Reunion, was there anything the duo rejected as too much? "It's not a question of is it too outrageous or shocking," says Schlossberg. "It's more, is this in character, or is this believable?"

While there is gross-out humour in the American Pie series and Harold & Kumar, it's balanced with a goodheartedness. In short, one minute they're turning your stomach, the next warming your heart.

"Our comedy tends to come from a good place," says Hurwitz, 34. "We like to have a focus on character, we like to write likeable characters, people you would want to be friends with. American Pie is no different from that. They are movies about friendship, relationships, family. Real things that inherently have a lot of heart."

Striking a balance can be difficult, he adds. "It is a challenge to make sure that you are not getting too sappy or going too harsh in certain ways."

That balance is much in evidence in Harold & Kumar. If you disregard the sex, drugs and sheer rock and roll nature of it all, H&K could be defined as a sweet, old fashioned buddy movie.

"Harold & Kumar is the classic odd couple," says Hurwitz. "They just happen to be a Korean American and an Indian American."

Schlossberg says only the first movie, Harold & Kumar Get the Munchies, bore any resemblance to their lives long ago.

"That felt like what our lives were like at the time, which is basically we would work during the day and at night the big decision was what were we going to have to eat.

"When you're young, not married yet, don't have families, living in a not so great apartment, what cheap food you are going to have for dinner becomes the big question in life. That silly, meaningless time in your life is what we wanted to portray in that movie."

The duo are unusual in Hollywood in that they didn't go to film school or attend writing classes. They are not, like the Coens, Weitzs, or Farrellys, comedy writing brothers, though Schlossberg says they've been friends for so long they feel like brothers.

Their training, says Hurwitz, was watching movies, noting what made people laugh. Fourteen years on from when they started writing together they have their own shorthand now, know what each other think. And one of the films they watched over and over, then bought on DVD? American Pie, of course. For Schlossberg and Hurwitz, a history and finance graduate respectively, it turned out to be a smart investment.

American Pie: Reunion opens on May 2