Rapper Nas was joined onstage by Alicia Keys when he performed his debut album Illmatic in full for the star-studded audience at the premiere of his new documentary. The Tribeca Film Festival opened in New York City on Wednesday (16Apr14) with the first screening of Time Is Illmatic, about the making of Nas' seminal 1994 record. Robert De Niro, who co-founded the festival, introduced the film to the crowd at the Beacon Theatre, but the real show began after the credits rolled, with Nas performing Illmatic in its entirety. Keys graced the stage, playing the opening piano riffs from her anthemic track Empire State of Mind. Guests at the screening included rapper Wale, Keys' husband Swizz Beatz and actor Anthony Mackie.