By James Hibberd

LOS ANGELES (Hollywood Reporter) - "Snakes on a cane." Sound familiar?

Perhaps, during commercial breaks on Fox, you've seen the flashes of a caduceus that uses a cane instead of a staff. You might have seen the symbol drawn with chalk on New York streets. Or even clicked through to the phrase's cryptic Web site.

Fox is set to announce what many who have spied the symbol already suspect: It has been a summerlong guerrilla marketing promotion for Season 6 of "House" in the fall.

Yet few would guess that the idea came from "House" star Hugh Laurie.

In the spring, the actor thought of the "snakes on a cane" phrase, sketched the symbol and mentioned it to Fox's marketing department, which ran with the idea as an innovative teaser campaign.

"Teaser campaigns are usually reserved for Year 1 shows," Joe Earley, Fox's executive vice president of marketing and communications, said. "Rarely would you do something like this for a show that's already established."

"House" is set to return September 21 and likely will continue its reign as the network's highest-rated drama. Usually networks reserve their most creative marketing efforts for new shows, but Fox elected to buck tradition to promote its veteran hit. But with competitors launching three new medical dramas this season, "House" could benefit from some extra attention.

The first part of the campaign spread the symbol without any context. The second phase added a clock counting down to the "House" premiere date on the campaign's Web site and five-second "subliminal" ads during Fox programing, which remained cryptic and avoided showing a direct connection to "House." One ad was a full-page placement in a major publication without a title or tune-in date.

Online viewers' myriad guesses about the symbol have ranged from something related to the president's health care plan to a campaign for a new movie.

"We were really able to hit a wide range of people," Earley said. "'House' doesn't need a teaser campaign, but given how brilliant it is, it's intrigued people in a new way."

The crucial part is ensuring that viewers make the connection between the teaser "snakes on a cane" imagery and "House." So Fox is set to embark on the next phase of its campaign: In addition to ads on the air and off, the network will have a vintage ambulance driving around Los Angeles bearing the symbol and tune-in information for the show.

(Editing by SheriLinden at Reuters)