*Jennifer Hudson surprised the crowd at a show in Barbados last night by bringing her young son on stage to sing with her…and he handled his biz.

At the ripe old age of 18 months, David Otunga, Jr. made his stage debut alongside his mama during her concert at Barbados’ Holder House venue.

Before and during her current single “Where You At,” Hudson passed the mic to her child so he could join in. [Watch below.]

In a subsequent post on her Twitter.com page, she wrote, “It was a very good crowd at the show here… I love a crowd that give back to u what u give them !!!”

[Below: The person filming figures out the camera is sideways at about 1:18.]