Rapper Eminem closed out Lollapalooza 2014 in grand style with a great concert performance that included a surprise guest appearance from Rihanna.

With less than a week away before the duo co-headlines the Monster tour, the superstar pair gave fans a quick preview of what to expect on the trek.
Dressed in a grey jersey shorts, a white T-shirt printed with LL Cool J's 'Bigger and Deffer LP' cover, Em graciously brought out RiRi who wore a black mini-dress and matching sheer shawl.

Together they performed Eminem's classic 2000 single 'Stan' as well as their duets, 'Monster' and 'Love the Way You Lie.'

"Thank you @Eminem and Chicago for letting me share this moment with you at #Lollapalooza,” tweeted Rihanna after her appearance.

Before Rihanna came out, Em ran through a medley of his classic tunes including 'The Real Slim Shady,' 'Kill You,' 'Lose Yourself,' 'My Name Is' and many more. The Detroit spitfire ended his show with a rendition of 'Not Afraid' and dedicated to "anyone who's ever lost someone."

Meanwhile, Eminem and Rihanna's The Monster tour kicks off this Thursday, Aug. 7 at the Rose Bowl in Pasadena, Calif.

Watch Eminem and Rihanna Perform 'The' at Lollapalooza 2014

Watch Eminem and Rihanna Perform 'Love the Way You Lie' at Lollapalooza 2014