Watch: Serena shares heartfelt message to daughter in new ad

Serena Williams has some words of advice to any young girl pursuing sports: Keep playing.

In a new spot from Gatorade, the tennis star is seen cradling a baby that's supposed to be daughter Alexis Olympia Ohanian Jr. - played by a body double, according to Ad Age's E.J. Schultz - and telling her, "I won't mind if you never choose to pick up a racquet, but I beg you in this game of life, please keep playing."

The ad is part of the new "Sisters in Sweat" campaign, which encourages girls to continue playing sports regardless of whether they hope to do so professionally.