There seems to be no stopping the popularity of the best-selling graphic novel The Art Of Charlie Chan Hock Chye by Singapore cartoonist Sonny Liew.

An exhibition of original artwork for the 300-page tome, first published by Epigram Books last year, has seen brisk sales since it opened last Friday at Mulan Gallery in Armenian Street.

Timed to celebrate the launch of the international edition of the novel by American imprint Pantheon Books, the show features some 90 works including original comic pages and paintings.

Of them, 39 drawings in pencil and ink on paper are available for sale. The works are priced between $250 and $1,400 and include drawings of characters in the book such as the superhero Roachman and Singapore's founding prime minister Mr Lee Kuan Yew.

Five pages were sold on the opening night and the gallery has received multiple requests from collectors for the artist to sell other comic pages not displayed in the show.

Gallery owner Patricia Liang, 47, says: "We were surprised to find clients who previously never bought comic pages, buying works for the first time.

"A client who is away from Singapore even got her parents to come down to the opening to pick out works for her."

The fine art gallery has been exhibiting works by Liew, a three- time nominee for the Eisner Awards - the Academy Awards of the comic-book industry - since 2009. Previous exhibitions included comic pages from his novel Malinky Robot (2011) as well as artwork for the novel The Shadow Hero (2014), authored by Gene Luen Yang.

Liew, 41, who selected the works on display in this show, says he picked both sketches and final drawings to reflect the range of styles and approaches in the novel.

The premise of the book is the life of the fictional Singapore comic artist Charlie Chan Hock Chye, a forgotten pioneer of the comics industry in South-east Asia. Woven into the biography is the evolution of comic book styles and the history of Singapore.

The story includes a leftist revisionist telling of the life of the former Barisan Sosialis leader Lim Chin Siong and its "sensitive content" led the National Arts Council to withdraw an $8,000 publishing grant for the book.

Of the exhibition, Liew says: "I'm never too keen to sell artwork. You spend a lot of time creating them so there's a feeling of attachment.

"This book is probably the most personal I've ever done, and maybe the most significant to date, so for me, it's more about wanting to share the original art in an exhibition rather than selling them."