Katy Perry, an outspoken supporter of Hillary Clinton, was surprised Tuesday night at the UNICEF Snowflake Ball in New York when the former Democratic presidential nominee presented her with an award.

Perry, who campaigned for Clinton at a rally at University of Nevada, Las Vegas, and dressed up as the politician for Halloween, received the Audrey Hepburn Humanitarian Award. The award honors the "Breakfast at Tiffany's" actress, who worked to support for UNICEF programs and to increase awareness of the issues affecting children worldwide.

Perry didn't know that Clinton would be at the awards ceremony.

"I have seen Katy's commitment to the causes she believes in firsthand," Clinton said before presenting Perry with the award. "I've gotten to spend time with her, and I know how deeply she cares about making our world a better place. She is serious about understanding the complex problems we face and pulling people together to solve them."

Perry has been a UNICEF ambassador since 2013.

"She's someone whose powerful voice and creative lyrics remind us when you get knocked down to get back up," Clinton said of the "Roar" singer. "We need champions like Katy now more than ever, her passion, her energy and, yes, her voice, louder than a lion."

Perry thanked Clinton and gave her credit for helping inspire her.

"I've always had a voice -- a singing voice -- but I've never had a voice like I've had before," an emotional Perry said. "Hillary Clinton has lit a voice inside of me, and that light will never go out. It will continue to get brighter and brighter. Thank you, Hillary. You motivate me and so many millions of people. We appreciate you for your incredible work and your heart."

According to CNN, Perry attended the event with her parents and boyfriend, actor Orlando Bloom.