What a crowd!
The Wrecking Ball singer hopped on stage in front of the 2,000 attendees for a dance warm up with celeb pilates instructor Mari Winsor, who is battling the disease. After dancing to Pharrell's Happy, the 22-year-old shared:
"I'm already sweating. She had us doing a happy warm-up and she kicked my ass once again. She's done it for years and she's already done it this morning and it's only 11!"
LOLz. Exercise for a good cause!
Some of Hollywood's biggest names also came out to support power publicist Nanci Ryder, who was diagnosed with ALS two years ago.
Notable "Team Nanci" members included: Reese Witherspoon with husband Jim Toth and daughter Ava Phillippe, Renée Zellweger with musician boyfriend Doyle Bramhall, Courteney Cox with daughter Coco Arquette, Angie Harmon, Justine Bateman and DreamWorks Animation boss Jeffrey Katzenberg.
This is a cause that Miz Witherspoon, 39, genuinely cares about. She shared:
"I'm just happy to be here supporting Nanci but also just raising awareness and raising money for ALS. There's so much that's not known about this disease and watching our friend progress every single week with something different and not know is so horrible. There are so many families living with this devastating disease. It's time that we start doing something to create a cure, to find what the root of the problem is and eradicate it because it's just unbelievably devastating."
See some more pics from the fundraiser (below)!