The tennis star won't be pitching designer threads for a fancy clothier. She will be strutting her stuff in commercials for a sneaker maker - Reebok International.

Reebok is casting the 2000 US Open and Wimbledon champion in genteel environs in an effort to lend a touch of class to its admittedly worn-out image. Though young consumers frequently respond well to new Reebok shoes in marketing focus groups, they thumb their noses after discovering who made them, the company says.

"We have a brand that hasn't been held in the highest regard," Reebok chief executive Mr Paul Fireman concedes.

The Stoughton, Mass., company vaulted to the top of the sneaker world in the mid-1980s by selling women affordable shoes often promoted through aerobics classes. It had fallen to No. 3 by 1999, behind Nike and Adidas. It accounts for 12 per cent of athletic-shoe sales in the US, in part because teenagers tend to view the shoe as their parents' brand. Young males, who often set sneaker trends, see Reebok as a woman's thing. Nike, the market leader, has higher average prices - so some consumers regard Reeboks as cheap goods.

Reasoning that it is time for a new marketing twist, Reebok has whittled the number of athletes it pays for endorsements to fewer than 500 from more than 3,000 two years ago. This has slashed $70 million from its cost base. The savings - along with other cost cutting - helped it triple earnings during the first nine months of 2000 to $74.7 million, leading to a big surge in its stock price.

But sales, at $2.2 billion for the same period, are flat. Aiming to spur them on, Reebok will double its US ad spending this year, to about $90 million, and seek to carve an image that is distinct from Nike's projection of cool, athletic prowess.

By casting an athlete in a nonathletic role, Reebok hopes to build the perception that folks who wear its goods are iconoclasts. Its new marketing mantra, unveiled in the Williams ad: "Defy convention."

Reebok will air the Williams spot during the first installment of "Survivor: The Australian Outback," which immediately follows the Super Bowl game on January 28. CBS charges less for commercials during "Survivor" than it does the Super Bowl. "Survivor" also skews to a younger audience, one that is more in line with the 16-to-24-year-olds that Reebok believes it needs to woo.

The smash success of the first "Survivor" series gave Reebok a big boost last year. Its eight commercials for the adventure-game series featured a pair of guys stranded on an island with offbeat and off-color themes. One scatological spot gained Reebok extra attention when CBS, a unit of Viacom, pulled it prior to airing. Reebok capitalized on the controversy by putting the banned commercial on www.survivorsucks.com (www.survivorsucks.com), a popular Web site, where it gained a lot of buzz.

" `Survivor' put us back on the map," says Mr John Wardley, Reebok's vice-president of brand communications.

The latest ads were created by Berlin, Cameron & Partners, of New York, the same agency that created the previous "Survivor" ads.

Mr Fireman characterises Reebok's turnaround plan as a three-year effort aimed at increasing its market share more than six percentage points, which would put it near the 20 per cent it had the early 1990s. "This is a perception business," he says. "It's not so much what you do, but how you are perceived."