Tennis Star Novak Djokovic Goes Shirtless For Ice Bucket Challenge - Watch Now!

Check out Novak Djokovic going shirtless while accepting the ALS Ice Bucket Challenge!

“Johnny Mac, @niallofficial, Bernard & @sabinelisicki thank you for nominating me for #ALSIceBucketChallenge ACCEPTED,” the 27-year-old Serbian tennis player tweeted.

PHOTOS: Check out the latest pics of Novak Djokovic

After completing the challenge, he wrote, “Proud to be part of #ALSIceBucketChallenge. I donated as well. I challenge you @ConchitaWurst, Mr. Bean & @jumpman23!”

Also pictured: Novak rocking a plaid shirt while making an appearance on The Late Show with David Letterman on Tuesday (August 19) in New York City.