From the roster of Joey Bada$$' hip-hop collective, Progressive Era, CJ Fly celebrated surpassing 15,000 followers on Twitter (@FLYestintheeERA) by treating his fans to some new material.

Set to feature on his upcoming debut mixtape, 'The Error' is a laid-back, old school track, produced by Spanish duo Cookin' Soul, which takes its inspiration from fellow Pro Era member, Capital STEEZ, who passed away in December.

The tune was posted online last night, along with this message:

"My pro Capital STEEZ considered the Progressive Era as an contradiction and since he was my inspiration for this song I decide to make the title have deeper meaning too. We make the ERA, they make the error. So turn your speakers on max and listen carefully. Hope you love it #LONGLIVESTEELO" - CJ Fly