Betty Wright has died at the age of 66.
The soul singer's death was confirmed by her niece.
Last week, singer Chaka Khan had asked people to pray for Betty.
She wrote on Twitter on May 3: "Calling all my #PrayWarriors. My beloved sister, Betty Wright @MsBettyWright, is now in need of all your prayers."
Betty was a talented R&B singer who popularised the phrase, 'No pain no gain'.
Her cause of death is not yet known.
Betty has been described as one of the most underrated singers of her time by others in the industry.
Her hits includes 1971's Clean Up Woman, which she released when she was just 18, Let Me Be Your Lovermaker and Where Is The Love.
In the 1980s, Betty made a bold move by launching her own independent label, something that had never been done by a female artist before.
It was after that that she recorded her song No Pain (No Gain), which went on to become a popular phrase.
She broke ground again with her album Mother Wit, which went gold.
It was the first time an African-American female singer went gold on her own record label.
She became an inspiration to a number of hit singers, including Mary J Blige and Joss Stone.
Betty, who was born Bessie Regina Norris, even teamed up with Joss to record song The Art of Love and War.
Her singing career began at an early age, when she started performing with Echoes of Joy, her family's gospel group in Miami.
She released her first solo album, My First Time Around, by the time she was 15.
She won a Grammy in 1974 for her song Where Is The Love.
The star is survived by her four children.
She tragically lost her son Patrick in 2005, when he was shot and killed at age 21.
