They're not exactly tardy to the party, but Roger Federer and Rafael Nadal have added their voices and their shivering bodies to the ALS Ice Bucket Challenge brigade. Federer accepted the call from Anna Wintour, Gavin Rossdale, and Ana Ivanovic (not bad company); Nadal took a dunk thanks to a range of invites, and nominated the likes of retired star Carlos Moya and retired soccer great Ronaldo to go next.

Federer, of course, performed the act gracefully:

To his credit, Nadal sort of turned it into a one-man wet T-shirt contest:

Federer put it well on his Facebook page: "ALS is a tragic disease, and I hope that the social media attention from the Ice Bucket Challenge continues to bring more awareness and donation dollars to curing ALS. Funny videos are entertaining, and can be important to raise awareness, but a more important measure of impact is donating: www.alsa.org/"

Despite wearing a wrist splint for the injury keeping him out of the U.S. Open this month, the Spaniard didn't struggle to raise the bucket over his head. "I'm accepting #ALSIceBucketChallenge to raise awareness on ALS," Nadal and his team wrote on Facebook.

Each appeared to take his bath under some truly cold water, as evidenced in the reaction shots. The two join fellow pros Ivanovic, Novak Djokovic, Grigor Dimitrov, Caroline Wozniacki, and many more in going through with the challenge in recent days.

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