Last month, A$AP Rocky shed some light on his Hit-Boy-produced posse cut, "1 Train," and gave some praise to Big K.R.I.T. for his killer verse. And now, the Harlem rapper reveals how it all came together and why he chose the rappers he did. For those unaware, it features Rocky trading verses with Kendrick Lamar, Joey Bada$$, Yelawolf, Danny Brown, Action Bronson and K.R.I.T.

Watch the interview clip above.