Letta Mbulu knew and worked with Hugh Masekela for years. Hugh brought her to Herb Alpert's attention and she signed with A&M Records in June 1976.
In 1977, Letta lent her voice to the soundtrack of Roots: The Saga Of An American Family.
She recorded three albums for A&M. The third was titled Sound Of a Rainbow, never released by A&M but on a different label.