Today has been a crazy day for new music, but I'm loving every second of it. Just when I think no more amazing tunes will drop, producer Hit-Boy tweets out a link to a new song he produced for Kendrick Lamar. This track is called "Backseat Freestyle" and will be on Lamar's anticipated debut, good kid m.A.A.d. city, due October 22nd. And of course you know that Lamar kills it as usual. Stream the song below.