Chris Rock just posted a picture on his Instagram of him being in the studio with Eminem.  No word on exactly what they were recording in the studio but the picture has certainly raised interest.  

The comedian Rock has been known to make cameo's on different hip hop records over the years, most recently on "Blame Game" with Kanye West.  
Eminem has always been known for his spontaneous and funny sense of humor and perhaps Chris Rock will make an appearance on Em's new album, which is rumored to drop now July 2nd.  

Last fall Eminem appeared on the 50 Cent's song "My Life" and has been fully hands on producing his protege Skylar Grey's debut solo Album, Don't Look Down which releases on July 9th.  Eminem also had a rap and cameo in Skylar Grey's video for her single, "C'mon Let Me Ride".

Eminem has confirmed dates Aug 15-25 in Europe and will close his time out there headlining this year's Reading and Leeds Festivals in the UK over the weekend August 23-25.  Reading Festival have announced this year's Headliners which include Green Day, Biffy Clyro and Eminem. Also playing the festival this year are Fall Out Boy, System of a Down, Deftones, Bring Me The Horizon, Nine Inch Nails, New Found Glory, Frank Turner, Brand New, Skrillex, The Lumineers and more. 

Fans are still waiting on official word for U.S. dates, but with the new album dropping this summer, most are thinking surely he will do some U.S. touring at some point.  

Tyler the Creator and Kendrick Lamar are rumored to be joining Eminem on his 2013 tour dates. Also possible would be 50 Cent or his female singing protege Skylar Grey.