DENVER — At least two companies who have signed Denver Broncos quarterback Tim Tebow to represent their brands say it's paying off.

The companies aren't releasing specific numbers, but energy product firm The FRS Co. and Jockey International Inc. said they've seen a sharp spike in interest online since tying themselves to Tebow.

It doesn't hurt that Tebow regularly uses FRS chews on the sidelines during games. This week, unasked, Tebow wore an FRS hat in front of cameras as Denver prepares to face the New England Patriots on Saturday night.

"When Tim wore our beanie the other day for an interview, we saw a 500 percent increase in our web traffic immediately. Literally immediately," FRS CEO Carl Sweat said.

Foster City, Calif.-based FRS learned in the spring of 2010 from a GNC store manager that the Heisman Trophy winner was regularly buying the company's energy powders and products in Florida, where he won two national titles. FRS later got a call from the Broncos, who said their new quarterback wanted to get a hold of their products.

After a courtship that included takeout and games of Taboo at Tebow's home in Colorado, Tebow agreed to endorse FRS. The company ships him cases of its products and has given him an undisclosed amount of equity in the company.

Tebow also is a pitchman for Nike and Jockey, who didn't reveal terms of his deals.

Since signing Tebow in July 2010, Jockey has seen its Facebook fans increase by nearly 2,000 percent to more than 193,000 said chief marketing officer Dustin Cohn. Jockey's new staycool line, which launched with advertising that featured Tebow, is the fastest-selling collection in history for the company, in business since 1876.

Now Jockey is putting up more than $1 million for a contest for people who sign up on their website. If Tebow and the Broncos win the Super Bowl, one lucky person will receive $15,000. About 40,000 others will get $25 gift cards for Jockey products. So far more than 50,000 people have signed up, not including people who are automatically entered by buying Jockey gear, Cohn said. That's more than double the people the company expected would register.

Tebow has been an athlete for Nike since March 2010, before the Broncos drafted him.

Nike, whose roster also includes star NFL quarterbacks Aaron Rodgers and Drew Brees, isn't discussing its sales figures or what influence Tebow might have had on them, but North American revenue growth has been healthy.

"Tim is a dynamic athlete. He certainly seems to inspire folks with his play. That's the kind of thing we're looking for in all guys who become Nike athletes," Nike spokesman Brian Strong said.

FRS, whose other athletes include Lance Armstrong, said there are a number of reasons its retail business grew more than 100 percent last year, with similar growth expected for this year. But signing Tebow has been worth it.

Tebow has written letters to 7-Eleven, Circle K and other chains saying he'd love to see FRS on their shelves, Sweat said.

"We're getting customers calling us back that we couldn't engage with nearly as well before," Sweat said. "It's amazing what this young man does, not just on field but the way carries himself. His charitable work speaks to a lot of business leaders."

Plans are already under way for what FRS might do if the Broncos manage to make it to the Super Bowl.

Tebow was born in the Philippines where his parents were missionaries. Cameras have caught him singing hymns while warming up. He also has his own charitable foundation.

His off-the-field demeanor isn't an act, said Sweat, who has hung out with the Tebow family and remembers seeing the quarterback jump up eagerly to answer the doorbell on Halloween and get down on bended knee to talk with trick-or-treaters.

"I can't get him not to call me Mr. Sweat," Sweat said.