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.

Vice President Kamala Harris will attend rallies in Philadelphia and Pittsburgh on Monday night ... pitch The Vote for Freedom Rally will feature musical performances by Lady Gaga, Ricky Martin, The Roots, and more at 2600 Benjamin Franklin Parkway ...

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 "The Edge of Glory.