LL Cool J won't perform in the Wawa Welcome America Fourth of July Concert on Benjamin Franklin Parkway on Friday, saying he won't "cross a picket line" amid the ongoing strike in Philadelphia involving the city's largest municipal workers' union.

A sour note for Philly's Party on the Parkway. Both headliners of the Wawa Welcome America Fourth of July concert, LL Cool J and Jazmine Sullivan, have canceled their performances, refusing to cross the picket line as the strike by thousands of city workers stretches into its fourth day.