Kevin Durant signs with Sparkling Ice

Kevin Durant has signed another major endorsement deal since switching agents to Jay Z's Roc Nation Sports.

The Oklahoma City Thunder forward signed a deal Monday to endorse Sparkling Ice, a zero calorie carbonated water drink that is one of the fastest growing beverage brands in the U.S.

Terms weren't disclosed.

"I've always challenged myself on the basketball court, but this offseason is really the first year I'm challenging myself off of it -- on the business side," Durant told ESPN.com. "This is a brand I drink every day that I love and I wanted to be a part of it. I want to help them get to the next level."

Sparkling Ice for the past couple years was a sleeping giant in the beverage industry, going from $25 million in 2010 to expected revenue of $500 million in 2014.

With a target on their back, knockoffs abound and international expansion on the horizon, Kevin Klock, CEO of the brand's parent company Talking Rain, said the time was now to join forces with a major sports star.

"We frankly hadn't moved into athlete endorsements because we craved authenticity," Klock said. "Things fell into place when Kevin came to us."

Michael Yormark, president and chief strategy officer of Roc Nation Sports, said that Sparkling Ice came up in an initial meeting with Durant and his agent Rich Kleiman.

"He told us that this brand was already a part of him and he wanted to have an official relationship," Yormark said.

Klock said the plan is to use Durant as the company begins international expansion outside of the U.S., Canada and Mexico. He also said the company will use Durant to get into other segments of the beverage marketplace.

Durant had been an endorser of Gatorade until last September. Other deals Durant signed include Kind bars and the "NBA 2K" popular video game series.