Madonna celebrating while guests were seen raising a glass of Perrier-Jouët champagne at Rihanna’s Gala Afterparty at 1 OAK NYC

After the Met Gala, and after the party, those in the know headed to1 Oak NYC to party at Rihanna’s p-a-r-t-y.  Perrier-Jouët, Absolut Elyx and Tequila Avión flowed while A-listers showed up, dressed down after the high-pressure white carpet of the yearly Met Gala.

Rihanna celebrating with Perrier-Jouët champagne at her Gala Afterparty at 1 OAK NYC .

Guests literally let their hair down and enjoyed the company of other celebs. Spotted:  Madonna, Leonardo DiCaprio, Katy Perry, Pharrell, Kendall Jenner, and many, many more.