The 20th anniversary of Philly's Welcome America July 4th festival will feature music from John Mayer, J. Cole, Grace Potter, Jill Scott, Ne-Yo, Demi Lovato – and, of course, the Roots.

Mayor Nutter, joined by Black Thought and ?uestlove, announced the lineup at a press event Thursday in the Vista Room on the 50th floor of the 1717 Arch St. building, which overlooks the Ben Franklin Parkway where thousands will gather on the Fourth.

The festival is actually a weeklong event (July 1 to July 7) that includes Taste of Philly, screenings of "Rocky" and "Silver Linings Playbook" and a 4.5 ton hoagie.

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