The 29-year-old "Born This Way" singer was blocked from leaving the Cipriani 42nd Street where the event took place. Security had to force the group out of the way, reported Ace Showbiz.
The animal rights activists held up signs and shouted at her as she made her way into her awaiting car. The group stood in the middle of the street and continued yelling at her while blocking her chauffeured car from leaving.
Amid the chaos, her supporter was overheard scolding the protesters, "Leave her alone!"
"I would like to thank my fans from the bottom of my heart for loving me and my music, everything I have today is because of you. Always remember that if you work hard and dream passionately you can accomplish something so fantastic it's actually beyond your imagination. That's how I felt today. I'm living in a fantasy so amazing, not even on my best days as an artist could I have envisioned it," she wrote.