Nas was invited to perform with Jay-Z during his special two-night concerts at the Carnegie in February for the United Way of New York City and Shawn Carter Scholarship Foundation.
"I never thought two project dudes would be on the Carnegie Hall stage," Nas said at BET's 106 & Park.
Nas also revealed that the two rappers talked about fatherhood.
"He was like, 'Why you ain't tell me about this, man?' Nas said. "He's cool. Congratulations to him and Beyoncé."
In January, Jay-Z and Beyoncé welcomed their first child together, a daughter named Blue Ivy.
Watch the music video for Nas's 'Nasty' below: