Clinton makes surprise appearance at UNICEF gala, introducing singer Katy Perry

Hillary Clinton made a surprise appearance at the UNICEF Snowflake Ball in New York City on Tuesday night.

Clinton introduced UNICEF Goodwill Ambassador and singer Katy Perry at the annual event. Perry received the Audrey Hepburn Humanitarian Award.

The Snowflake Ball honors UNICEF's lifesaving work for children throughout the globe.

The Manhattan event has raised $27 million over the past eleven years.

When introducing Perry, Clinton said, "We need champions like Katy."

Perry was a big supporter of Clinton’s presidential run and campaigned for her across the nation.

The Associated Press contributed to this report.