Never underestimate the allure of a mystery. Filmmaker Robert Campbell doesn’t.

In the last 18 months, whenever he wore a hat emblazoned with the word "Ecila," people wanted to know what it meant and how they could get a hat of their own.

Campbell is a 26-year-old camera assistant with credits on "Lost," various movies and now "Hawaii Five-0." But his passion lies in creating his own films, and together with buddy Darieus Legg, he produced a movie they call "Ecila."

The film — their first major project — was a sellout when it premiered at the Hawaii International Film Festival, and the two men say their "Ecila" hats helped fill the theater’s 420 seats.

It was old-school social media.

"They weren’t for sale and nobody knew what they were," Campbell said. "There was that question, that mystery — What is ‘Ecila’? — and then people couldn’t pronounce the name. People couldn’t get it in stores, and they wanted it even more."

Legg, who directed the movie, initially had three hats made — for himself, a friend and Campbell. Now there are more than 1,000 out there, on heads in Hawaii, New York, London and Japan.

Pro surfer Andy Irons has one. Playboy centerfold Sara Jean Underwood has one. Scott Caan, who plays "Danno" on "Five-0," wore one during a CBS interview.

Campbell would travel with a box of 10 and invariably call home for a shipment of 100.

And always, there was this kicker: The hats were free.

"I like the fact that it is a gift," Campbell said. "I think it’s more memorable and more personable."

The pair won’t discuss the cost of the hats, only that it rivaled the cost of the film. But the hats gave them a way to spread their love of filmmaking and their dark story of villains and antiheroes.

"It completely put the name and the logo on the forefront of everyone’s mind," said Legg, who has a degree in marketing. "It was a serious branding tool. It was a small phenomena that people really enjoyed."

On the set of "Five-0" the hats are practically a uniform among the crew, but it was still a pleasant surprise when 75 people from the series arrived at the premiere, including the crime drama’s principal stars: Alex O’Loughlin, Caan, Daniel Dae Kim and Grace Park.

"It was overwhelming," Legg said. "The whole feeling was surreal."

Now here’s the spoiler to the mystery of "Ecila": It’s "Alice" spelled backward.

SHE DIDN’T HAVE a speaking part, got no credit at the end of the show and if you blinked, you missed Q’orianka Kilcher’s screen time on last week’s episode of the FX biker gang drama "Sons of Anarchy."

But you’ll get another chance Tuesday night. The star of the locally produced film "Princess Kaiulani" signed up for three more episodes. She plays Kerrianne Telford, the daughter of one of the bikers.

TOMORROW’S EPISODE of "Hawaii Five-0" will feature local bodysurfing legend and retired city lifeguard Mark Cunningham as a surf industry CEO named Ian Adams. Looks like a one-time gig, though. If you check out the network’s trailer online, you’ll see the 55-year-old Cunningham being zipped into a blue body bag.

"What I’m telling friends is don’t blink or tune in late because you might miss me," he said.

HAWAII’S KELLY HU will make her "Five-0" debut Nov. 1, guest-starring as a public safety liaison to the governor in an episode shot last month aboard the Battleship Missouri Memorial.

A longtime fan of the original show, Hu was so thrilled to be part of "Five-0" that she agreed to pay her own way to the islands for the episode. She was in L.A. at the time but is now in China, which meant a longer journey when she returned to Hawaii earlier this month to shoot a second episode.

No word on whether Hu will get to use her martial arts training to kick butt on "Five-0."

AND THAT’S a wrap.

Mike Gordon is the Star-Advertiser’s film and television writer. His "Outtakes" column appears Sundays. E-mail him at mgordon@staradvertiser.com.