"I just had a baby," the singer said in a video posted by TMZ on Thursday. "Four days ago – my son Cassius!"
The 40-year-old R&B star was performing at the New York New York nightclub when he told the crowd that his girlfriend/manager, Alicia Etheridge, had given birth.
Bobby has a 16-year-old daughter, Bobbi, with ex-wife Whitney Houston, and three other children from previous relationships – Landon, 23, LaPrincia, 19, and Bobby Brown Jr., 17.
A rep for Brown did not immediately return calls when reached by Access Hollywood.
The news of the child comes at the same time as ex-wife Whitney announced her new album will drop in September.