Whitney Houston's Mom Cissy Houston Dead at 91

Cissy Houston, a Grammy-winning singer and the mother of late singer and actress Whitney Houston, is dead.

Cissy died Monday surrounded by family in her New Jersey home, where she was under hospice care as a result of Alzheimer's disease ... her daughter-in-law Pat Houston confirmed to TMZ.

She's being remembered by Pat as "a strong and towering figure" and "a woman of deep faith and conviction."

Cissy started her career in 1938 singing gospel with her siblings ... and she graduated to become a backup singer for the likes of Elvis Presley, Aretha Franklin, Chaka Khan, Dionne Warwick, Lou Rawls, Van Morrison, Jimi Hendrix and Roy Hamilton.

She also collaborated with Beyoncé, Luther Vandross, Paul Simon and Burt Bacharach ... among others.

As a solo artist, Cissy won two Grammy Awards for best traditional soul gospel album ... for her 1997 album "Face to Face" and her 1998 album "He Leadeth Me."

Cissy was born and raised in Newark as the youngest of 8 children. She had 3 kids of her own, including Whitney and former NBA basketball player Gary Garland.

Her death was first reported by the Associated Press.

Cissy was 91.