When burlesque performer Dita Von Teese announced via Twitter that she would rather eat a dirty sandwich than watch “Cirque du Freak: The Vampire’s Assistant,” it provided a perverse kind of impetus to see the film.

Although the film, which is based on author Darren Shan’s Vampire Blood trilogy, drew negative reactions from fans after the trailer was released, the movie is actually much better than what critics expected. For those who are still interested in vampires after watching “True Blood,” “Twilight” and “The Vampire Diaries,” “The Vampire’s Assistant” would not be a bad way to kill a night.

Adapted from the first three novels in a 12-book saga, the film begins when two ordinary schoolboys, Darren (Chris Massoglia, “The Hole”) and Steve (Josh Hutcherson, “Journey to the Center of the Earth”), wander into a traveling freak show. Simultaneously impressed by and envious of vampire Larten Crepsley’s powers (John C. Reilly, “Step Brothers”), Darren steals Crepsley’s magical pet spider.

The following day, the boys accidentally let the spider out of its cage, and it viciously bites Steve. Darren is forced to return to Crepsley for the antidote to save his friend. Crepsley offers to help him only if Darren promises to become his assistant and a half-vampire. Feeling guilty for stealing the spider and realizing that there is no other way to save Steve, Darren gives in. That night, the boy leaves the life he has always known by faking his own death.

Although the plot revolves around Darren, he is weakly portrayed by Massoglia as a static and uninteresting character. Massoglia’s stiff facial expressions make it difficult to differentiate whether the character is scared, surprised or infatuated. Thankfully, director Paul Weitz (“About a Boy”) made the wise decision to accentuate the supporting cast, which saves the show and makes the film worth watching.

Reilly undoubtedly gives the film’s most captivating performance. He successfully depicts both a hilarious oddball and a seriously devoted vampire, providing most of the comic relief throughout the film. Hutcherson has several scene-stealing moments in the movie as well, including the fight scenes, in which he truly acts like a pugnacious brawler.

The circus freaks that become Darren’s new family also add to the film’s entertainment factor. Madame Truska (Salma Hayek, “Across the Universe”), Crepsley’s lover, is a beautiful, hyper and oddly bearded psychic. However, when Truska goes into a trance, she becomes solemn and esoteric.

The film’s bizarre CGI werewolves are strangely endearing, like adorable pet animals — although their looks are clearly borrowed from the house elves in “Harry Potter” and Gollum from “The Lord of the Rings.” It really is a pity that Truska and the werewolves, and many other unique freaks in the circus, are not given adequate screen time to fully develop their characters.

It is similarly disappointing to see very little blood in “The Vampire’s Assistant” — it is a vampire movie, after all — but the hilarious freaks can surely offer the audiences a good laugh or two.

So Dita Von Teese, if you really are considering eating a dirty sandwich, I would say go watch the movie instead; it will be a better trade.

— Contact Joy Chen.