The Mania Days actress, 34, was spotted at a star-studded event in the Hamptons, held at Apollo Theater board member Ron Perelman's East Hampton estate.
Accompanied by stars such as Jamie Foxx, Lenny Kravitz, Jon Bon Jovi and Pharrell Williams, Katie Holmes was pictured dancing and sipping on cocktails.
Katie, who was seated next to Jamie Foxx, Ellen DeGeneres and actress Penny Marshall, looked stunning for the occasion in a black knee-length dress which featured sheer panels. She let her hair down in loose curls and wore natural make-up.
A source told People that when singer Lenny Kravitz took the stage, the A-list crowd got into the groove and starting dancing while taking breaks at their table to sip drinks – at one point, the actress was seen trying some of Jamie's cocktail.
The party – called Apollo in the Hamptons: A Night of Legends event – didn't stop there. The Django Unchained actor later joined singer Pharrell Williams during his performance and got former Secretary of State Colin Powell and Katie up to the stage to dance to the hit song Get Lucky.
At one point, the night's performers were rocking the stage as well, chanting, "Go Katie, go Katie!".
Once back on the dance floor, the former Dawson's Creek star was seen mouthing the words as she danced to Robin Thicke's hit, Blurred Lines and Jamie's 2009 hit, Blame It (On the Alcohol).
Russell Simmons, who posted a picture on Twitter of Katie dancing at the event, was overheard saying to the actress at the end of the charity bash: "I never knew you were such a party girl."