In a video recorded by Video Music Box and posted online, Nas revealed the name of his newborn.
"My son is born today, so shout-out to my son, Knight," the rapper says in a clip, which is stamped with Tuesday's date.
Kelis went into labor on Tuesday, but a representative for the singer had not confirmed details of her delivery as of press time.
The couple publicly announced the pregnancy in January after being married for four years. The pair appeared to be in good spirits months after the announcement as they solicited names for their child from MTVNews.com readers. However, just two weeks after the solicitations, Kelis unexpectedly filed for divorce from her husband.
The splitting process has been bitter, with the two arguing over finances in court filings. At one point Kelis took to Twitter to admonish Nas after the rapper posted a salacious picture of himself with a group of women on the site using singer Maxwell's account. Reports also surfaced on Tuesday that Kelis barred Nas from the delivery room while she was in labor.
While the once happily married couple continue to be at odds, Nas appears to be in a celebratory mood over the birth of his second child in the online video. (He also has a daughter from a previous relationship.) In the same video clip, taken at a neighborhood party at the rapper's native Queensbridge Housing Projects, Nas takes the stage to perform. He again shouts-out his son and also urges his fans to be cautious when watching news reports about his divorce proceedings.
"My son's name is Knight. That's what I named the young God, Knight," Nas tells fans. "Y'all heard it first. Don't believe nothing you hear in the media. I love y'all. Don't listen to that bullsh--. I love y'all, that's why I'm here."