Harris gets raucous ovation in brief appearance
Harris sent the crowd into a frenzy when she walked onto the stage at the United Center, with attendees jumping to their feet in surprise.
"It is so good to be with everyone this evening in this hall and everyone at home. This is going to be a great week," she said to more applause.
Harris also gave Biden his flowers, sparking chants of "USA!"
"And I want to kick us off by celebrating our incredible president, Joe Biden, who will be speaking later tonight," she said. "We are forever grateful to you."
Harris walked off to her campaign anthem, Beyonce's hit song "Freedom."