In the late 1990s, it would be hard to imagine Alec Su behind a camera. Then, the Taiwan star, who shot to fame with the band Little Tigers, was a heartthrob thanks to the hit television series My Fair Princess.

But now, Su is leaving the spotlight to his cast as he aims to be a good director.

Su was in Beijing recently to talk about his second directorial feature, The Devotion of Suspect X, a Chinese adaptation of Japanese author Keigo Higashino's classic novel with the same title.

The Devotion of Suspect X is widely regarded as one of Japan's best crime novels.

The book, which has received a series of awards in Japan, the United States and the United Kingdom, was adapted for film in Japan in 2008 and South Korea in 2013.

Both versions received critical acclaim.

But for Su, the previous success has only added to his anxiety.

"It (the filmmaking process) was very difficult," he says.

"I knew what was happening online, which put me under a lot of pressure."

When Su was picked to direct the film earlier last year, many diehard fans of the book questioned the Chinese investors' decision.

Su's directorial debut, The Left Ear, adapted from Rao Xueman's namesake coming-of-age novel, got just 5.4 points out of 10 on the country's one of the most popular review sites, Douban.com.

So, given Su's track record, many fans say they are unsure if Su is qualified to handle the story.

"I've received some threats (from netizens). Someone said he would never forgive me if I ruin his favorite novel," says Su, smiling.

"But since the first trailers were released, the situation seems better. Some netizens say the footage strikes the right note. It's really comforting."

As for other good news: Unlike some films that use young stars - ignoring poor performances - to maximize profit, Su got Wang Kai and Zhang Luyi, both graduates from the Central Academy of Drama, China's top acting university.

Wang became an A-lister for his remarkable incarnation of an upright prince in the hit series Nirvana in Fire. Zhang established his reputation as a talented actor for the revolutionary series The Red.

"I was lucky to get both of them," says Su.

But he admits that challenges remain. "I need to make a familiar yet brand-new film. Many people have read the book. They know what happens and how it goes. I need to dismantle the original tale and rebuild it in a Chinese way," he says.

Higashino, the author, wanted the Chinese screenplay to be different from the Japanese and South Korean versions.

"Higashino lives like a reclusive artist. Every time we sent him the script, it took nearly a month to get his feedback," Su says.

Despite the problems, Su believes he has made a quality, localized adaptation.

Wang Changtian, president of the Beijing-based production firm Enlight Media, explains the investors' selection of Su.

"Su was once the champion in an entrance examination to Taiwan's best high school, and later he was taken in by Taiwan's best university. His major is mechanical engineering. I believe Su is not only a star but also qualified and talented," he says.

The feature, which is in post-production, will be released across the Chinese mainland on April 1.