Eminem and Rihanna have officially launched their Monster tour.

The highly anticipated Monster tour kicked off last night at the Rose Bowl in Pasadena, California and the concert is simply "upredictable," as the Rolling Stones described it.

The six-date, three-city Eminem and Rihanna Monster tour began with a short film paying homage to "Silence of the Lambs." Yeah, we know, cooky right? The short film ends with Eminem, strapped to a hospital bed, being lowered onto a stage "shimmering with multimedia effect," according to the music magazine.

Eminem and Rihanna's collaboration track "Numb" kicked off the highly energetic show. The show started off with six-joint performances by the two mega-stars before Rihanna took the stage solo, launching into the 17-track set.

No need to fear Eminem fans, the "Rap God" hitmaker gave a solo performance as well after "Love The Way You Lie" was performed. The rapper played 20 of his hit songs.

The reviews for the overall concert were positive with the Rolling Stones writing, "'The Monster' appropriately summed up the themes that link these seemingly disparate performances; both in their own distinct ways, often use their art to expose their private demons. This tendency made the event still feel a bit more rebellious, unpredictable and raw than the typical big-name stadium concert."

Darren Franich of the Entertainment Weekly had a different stance on the concert.

"At one point, it all began to get a bit rambly; the night's grand-finale encore, the tour-titling 2013 hit "The Monster," came off as very energetic and very just-okay. Rihanna stood center stage, not so much dancing as gyrating gradually while Eminem raced around her, sweat pouring off his brow. It's hard to say what brings these two very different stars together, but it's fascinating to watch. Forget oil and water-this is gravity and anti-gravity," wrote the publication.