Rock bands don't get much bigger than Pearl Jam, but during their headlining set at Philadelphia's Made In America Festival on Sunday (Sept. 2), the group added even more star power to their set, teaming with rapper Jay-Z for an encore performance of '99 Problems.'

Wearing a Brooklyn Nets cap -- fitting, since he's part owner of the basketball team -- Jay-Z rocked the mic on his 2004 hit about racial profiling as the band played behind him. After Jay-Z -- who spearheaded the festival and headlined the first night -- left the stage, Pearl Jam launched into a cover of Neil Young's 'Rockin' in the Free World,' a longtime favorite of theirs.

The Made In America Festival brought together indie, hip-hop, soul and electronic artists, including Passion Pit, Dirty Projectors, Skrillex, Jill Scott and D'Angelo. Hip-hop legends Run-DMC performed for the first time in more than a decade, with Jam Master Jay's sons filling in for the DJ, who was killed in 2002.

The audio quality in the video below isn't the best, but you can feel the energy coming from the stage.

Watch Pearl Jam and Jay-Z Perform '99 Problems'