I've spent a lot of time trying to remember this one. It was with
M. C. Hammer, the black, once famous and rich rapper, and the
three children were white. He was trying to teach them how to
sing so that they could compete in a talent show to save their
house. The name of the show was "The Right Connections," originally
made in 1997. Hammer played the role of Kendrick Bragg. Here's a link:
The Right Connections (1997) (TV) - Synopsis