Killer Mike was introduced to El-P through a mutual friend who was an executive at Cartoon Network. Both rappers had done work for their after-hours program Adult Swim. They hit it off, and El-P helped produce Mike's album RAP Music, his most critically acclaimed project. Mike also appeared on el-P's album Cure for Cancer, which came out around the same time as RAP Music, so they decided to go on tour together. The tour was a huge success, so they decided to form a group called Run the Jewels.