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Eminem thrilled the Lollapalooza crowd during his closing set Friday night when he brought out surprise guest Rihanna

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About halfway into his set, Rihanna joined Eminem on stage for "Love The Way You Lie," and to say the crowd lost their minds would be an understatement.

Rihanna stayed to perform their latest hit together, "Monster," and then sang Dido's part with Em on "Stan." 

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Check out videos from the performance below!