The brunette beauty took the chilly challenge in a bikini top, posting two videos on Instagram to prove she went through with it.
"Thank you to everyone for challenging me to do the #icebucketchallenge to raise awareness for #ALS and I nominate @juleshough @riawnacapri @derekhough And on behalf of @eli_miz I nominate @caradelevingne," Nina posted alongside the first Instavideo, which showed her rocking shades and a tank top on a boat.
In the next Instavideo, Nina strips off her tank to reveal a black bikini top, saying, "Alright Tommy let's do it," as "Tommy" pours a bucket of ice water all over her. Then, Nina jumps off the boat into the ocean. "Challenge accepted. If you're gonna go in , you gotta go ALLLLLLL in. #ALS," she captioned the clip.
Jennifer Lopez also stripped down for the challenge, taking hers fresh from the gym. In an Instavideo, J.Lo showed off her abs in a black sports bra and black capri pants, as her friends and kids poured buckets of ice water on her in her backyard.
"After workout #ALSicebucketchallenge Thanks @cristiano @tracyanderson oh and @pitbull @thenewclassic @leahremini you've been challenged!
Celebs and people everywhere have been taking the challenge to raise money for the ALS Association to research Lou Gehrig's Disease. As of Tuesday, the organization had raised $22.9 million in donations for the cause.