Watch: Rihanna & Eminem preview their 'Monster' tour at Lollapalooza...
Lollapalooza kicked off last night, which saw Rihanna and Eminem preview their upcoming 'Monster' tour. The superstars performed their #1 collaborations 'Love The Way You Lie' and 'The Monster.' Plus, Rihanna took over Dido's verses for Em's hit song 'Stan.'
Watch a preview of their tour inside, which kicks off next week.
