VIDEO : Hillary Clinton Makes Shock Appearance To Honor Katy Perry

NEW YORK (AP) ? Katy Perry was the night's big honoree, but Hillary Clinton got the biggest ovation as the former presidential candidate presented the pop star with an award from UNICEF at Tuesday's Snowflake Ball. Her appearance at the event was a surprise, and Clinton got a sustained standing ovation from the cheering crowd. Clinton also said Perry's lyrics "remind us when you get knocked down to get back up" ? causing more cheers to erupt in the audience.