Lady Gaga was also among the celebs on hand. Earlier in the event she performed "God Bless America," and after Harris delivered her rousing get-out-the-vote pitch, she returned to the stage for a surprise performance of her classic,

Vice President Kamala Harris held a rally in Pennsylvania rally featuring Fat Joe, Lady Gaga, Ricky Martin, the Roots, will.i.am, and Oprah Winfrey.

Lady Gaga will join Vice President Kamala Harris at her final rally of the campaign Monday night in Philadelphia. It is the first campaign appearance f