Here's a flashback for your Friday: English radio DJ Tim Westwood recently revealed a never-before-heard Eminem freestyle from 1999.

During a London promotion trip for The Slim Shady LP, a 27-year-old Em and his D12 cohort Proof (who passed in 2006) spit a 13-minute freestyle in the studio. As Rap-Up notes, Marshall raps about everything from overdoing on mushrooms to his daughter. 

This isn't the first freestyle Westwood has in his vault. In November, the DJ revealed a previously unheard freestyle from Jay Z, also from the '90s

Get fully into the flashback mode with the accompanying visuals above, peppered with old photos of a fresh-faced Em rocking a do-rag and glasses in the studio.