Ms. Williams also appeared in movies and on television. She was a saloon singer in the Mario Van Peebles movie Posse and she had a recurring role on the television situation comedy Sister, Sister, playing actress Jackée Harry's best friend, Monica.
Ms. Williams possessed powerful, soulful pipes. Her initial success in the music industry came as a background singer for artists including Chaka Khan, Anita Baker, and Sting. But she would eventually establish her career with the release of her first album, Vesta, in 1986.
Over the years, she had hits including "Once Bitten Twice Shy," "Sweet, Sweet Love," and her signature song, "Congratulations."
Ms. Williams was supposed to perform at the 21st annual "DIVAS Simply Singing!" in Los Angeles next month. The Oct. 22 show will now pay tribute to her and another late soul singer, Teena Marie.
The 5-foot-3 entertainer gained weight in the 1990s, ballooning to a size 26. She went on a dramatic weight-loss program, losing 100 pounds and getting down to a size 6.
She went on to become an advocate for the prevention of childhood obesity and juvenile diabetes. - AP