Penning a good sequel is a tricky business in Hollywood, with many film-makers' attempts joining the merry-go-round of overstuffed, re-hashed originals.

So when Bad Neighbours struck a chord with audiences back in 2014, comedy genius Seth Rogen was determined his laugh-a-minute follow-up wouldn't suffer the same fate.

"You want it to capture the spirit of the movie people enjoyed [the first time around], but you don't want to do the exact same thing," says 34-year-old Rogen, who stars in and produces the franchise.

"It was important for us to come up with an idea that felt like it could be its own movie, a story that seemed good enough to sustain it.

"The conversation wasn't about how to escalate it; it was how to evolve it. We weren't trying to add more and make a bigger version of the first film, we wanted to explore the next thing that would happen in these people's lives."

Dubbed a "Gross, R-rated, dirty, disgusting Toy Story" by director Nicholas Stoller (Forgetting Sarah Marshall, Get Him To The Greek), Neighbours 2: Sorority Rising picks up with reformed party people Mac (Rogen) and Kelly Radner (Rose Byrne of Bridesmaids fame) preparing to make the final move into adulthood: the suburbs.

Just as the thirty-somethings think they've reclaimed the neighbourhood and are safe to sell, they learn that the new occupants next door are a sorority - Kappa Nu - who are even more out of control than Teddy (Zac Efron) and his fraternity brothers, whose outrageous parties tormented the couple in the first movie. And with baby number two on the way, it's a case of parents Vs the bond of sisterhood.

Heading up the unorthodox Kappa Nu, along with Beth (Kiersey Clemons) and Nora (Beanie Feldstein), is Shelby, played by Hollywood teen star Chloe Grace Moretz.

"I'm the perfect age for his kind of movies," announces the 19-year-old, thrusting her thumb in Rogen's direction. "When the first one came out, me and my friends went to see it. I'm a big fan."

Dressed in a ditsy floral jacket and tartan skirt, Moretz is the epitome of Tinseltown chic; her trademark blonde hair perfectly coiffed. But her youthful looks shouldn't fool you.

Brimming with confidence, the Atlanta-born star speaks with wisdom beyond her years, having worked the industry since her breakout big-screen role in the 2005 remake of The Amityville Horror, at the tender age of eight.

Sat shoulder to shoulder with her bearded co-star, who also made his mark at a young age - but on the comedy circuit, she's full of admiration for her character Shelby's fearless nature.

"It's a very modern character, in the sense that she's trying to hit the system in the face, but what's funny about it is that it's a bunch of kids trying to do it," reasons Moretz, whose other credits include Carrie and Kick-Ass.

"They're not the most educated on how to go about it, and they don't really know how to conduct themselves, so it's very true to our generation right now: trying to do a lot of things, but not really being equipped to take them on."

Of the feminist undertones that surface, she continues: "Shelby knows how to go after something and has insane tenacity.

"She is definitely empowered; she's not afraid to say, 'No', and doesn't let herself be pushed over by anyone, male or female."

Rogen agrees: "The girls have a clearer vision and a much more righteous goal, and because of that, go much further and are a lot scarier.

"Personally, I'm more afraid of Chloe, Kiersey and Beanie than I was of Zac [and the other boys]."

Moretz giggles, before adding: "What's cool about it, is a team of guys came up with the idea to make a story about a bunch of young women doing their own thing."

So how did an all-male team uncover the members-only world of sororities? Did they go to any parties?

"We didn't go to any!" cries Rogen. "I don't know if we'd be allowed!

"We talked to a lot of people who were in sororities, and we spoke to women to get their perspective," adds the Canadian comic, whose repertoire also includes Pineapple Express and Superbad.

"We spoke to women?" Moretz mimics, her face buried in her hands.

Between the laughs, the duo reveal that improvisation was a huge part of the film.

"A script is like the worst-case scenario, and this script was something we spent a lot of time on. But, it's impossible to predict if everything is going to work, and improv allows the actors to be organic and real in the moment," explains Rogen, who is married to US actress Lauren Miller.

For Moretz, it was an induction into the world of comedy.

"It was different for me, because most of the other movies I've done have been dramatic pieces and took a different approach," she admits. "I was able to be a total ham and get away with it, instead of having to hide my hammy-ness."

Encouraging improv allowed Moretz and her co-stars to add their voices to the choir, too.

"How can we have a social commentary on women within a movie written and created by a bunch of guys? It was cool that these dudes laid down their armour and encouraged our jokes, and they wrote what we wanted them to write," says the actress, who is currently filming the title role for a live-action adaptation of The Little Mermaid (Richard Curtis has penned the screenplay).

"One of the things we learned from the first film was that it was valuable to cast every small role with the funniest person willing to do it," notes Rogen. "It worked brilliantly, and everyone provided us with something extremely funny."

"I jumped in head first!" Moretz chimes, scanning for Rogen's response.

Smiling, he finishes: "That's all we ask!"

:: Bad Neighbours: Sorority Rising opens in UK cinemas on Friday, May 6