Beth Reekles was a teenager when she penned the teenybopper rom-com "The Kissing Booth", which went on to become a hit film and also spawned a successful sequel for OTT. A third instalment is in post-production.

This is not the first time a book for young adults or teenagers has been turned into a film. Several adaptations have become very popular, including the "Harry Potter" franchise, "The Vampire Diaries" and "The Princess Diaries" franchise among many others. Reekles decodes why such book adaptations are instant hits.

"For me, as a reader, it's always when the adaptation captures the heart and soul of the movie. Yes, characters might not look the way you imagined, and the adaptation might create new scenes and cut your favourite parts of the book -- but if it captures the emotion, the dynamics, the personalities that you loved in the book, that's when it can work really well," Reekles told IANS.

Reekles was 15 and was tired of stories of "vampires and werewolves" when she wrote her first young adult novel "The Kissing Booth", publishing it chapter by chapter on Wattpad, a story sharing site. It gained momentum from there.

"I was fifteen years old and desperate for a regular high school romance that didn't have the guy's best friend as a love interest. I loved the bad boy characters, but everything seemed to be paranormal romance at the time (which I loved, but was a bit tired of at the time). When I couldn't find the book I wanted to read, I wrote it instead!" said Reekles, who was feted with the Wattpad 2011 prize for Most Popular Teen Fiction.

The film version of her book series stars Jacob Elordi, Joey King and Joel Courtney. The 25-year-old writer is very happy with the way her characters are represented on screen and says she could not have a better cast.

"I think we couldn't have had a better cast! From the first moment I stepped onto set, I knew they were perfect -- Joey and Joel were in the middle of filming a scene, but I couldn't be sure if they were just goofing around, or actually being Elle and Lee," she recalled.

"In the book I make such a big deal out of Noah's ‘trademark smirk' -- the first time I saw Jacob do the smirk, I freaked out because it was exactly how I'd imagined," she added.

The author is now very excited about the third instalment of the film.

"I got to be on set for a couple of scenes and just loved it. I can't wait to see how the rest of the script and story comes to life -- and I can't wait for the soundtrack, too. I think these movies have such wonderful soundtracks," she said.

(Durga Chakravarty can be contacted at durga.c@ians.in)