In celebration of the 20th anniversary of his classic debut album, 'Illmatic,' Nas is giving fans a special treat -- a rare freestyle from his illustrious past.

The Queensbridge rapper released a freestyle he performed on the iconic 'Stretch Armstrong and Bobbito Show' on Oct. 28, 1993.

Over a melodic jazz-hop instrumental, Nas spits a flurry of gritty bars and some parts of his verse from 'Illmatic''s 'Memory Lane.' Also freestyling with Nas are rappers 6’9" and Grand Wizard.

This rare gem will appear on the second disc of the Sony Legacy release 'Illmatic XX,' which is the 20th anniversary reissue of 'Illmatic.' The double-CD collection, due out April 25, will feature 10 tracks from the original album and 10 additional songs of unreleased demos, remixes and freestyles.

In addition to the album, a documentary on the making of 'Illmatic' will premiere at the 2014 Tribeca Film Festival. The One9-directed movie, 'Time Is Illmatic,' will kick off the New York film festival on April 16. Following the screening, Nas will perform 'Illmatic' in its entirety.

Listen to Nas' '93 Stretch & Bobbito Freestyle Part 1 (Pre-Illmatic)