Danone Waters of America's water brand evian has launched a new 750ml sport cap in the US.

The brand has also appointed tennis player Madison Keys as its new ambassador.

The drink is positioned as an option for on-the-go hydration, at home, in transit, at work, or on the tennis courts.

Danone Waters of America's general manager Antoine Portmann said: "Madison Keys is an amazing representative for the evian brand and a natural partner for our latest innovation, the 750ml sport cap.

"Like evian, Madison understands that it's the source, where you start from, and the journey itself that shapes who and what you are. We're now excited to join Madison on her journey to athletic greatness, with evian by her side."

"Madison understands that it's the source, where you start from, and the journey itself that shapes who and what you are."

Madison Keys said: "I couldn't be more honored to work with evian, a company that understands that achieving excellence takes hard work, time, and commitment, the mindset that evian and I share. I look forward to a rewarding partnership with the iconic brand."

Madison is evian's first American brand ambassador. She will feature prominently in evian's advertising campaign around the 750ml sport cap, appearing in print, digital, out of home, and point-of-sale displays across retail channels in the US and Canada.

Madison joins Stan Wawrinka, Maria Sharapova, Lucas Pouille, and Lydia Ko as ambassadors for the brand.

The evian 750ml sport cap is available at drug, convenience and large retail stores nationwide for a suggested retail price of $2.29. evian's water is claimed to be sourced from the heart of the Alps.