The rapper told MTV News that the pair will know the sex of the baby in the next few days.
He said: "Yeah, man, I find out what it's gonna be next week, so I'm happy. I got another one coming in '09, yeah! That's what's up!"
Speaking on the red carpet at the Grammys, the musician confirmed that he is collaborating with Damien Marley and working to build new schools in Africa.
Nas recently revealed that he has recorded a guest vocal on Dr Dre's long-awaited Detox album.