The 32-year-old avid concert-goer from Sheffield was at the Ariana Grande show with her sister, Ms Claire Booth, 34, and Ms Booth's 11-year-old daughter, Hollie.
Relatives said Ms Brewster died trying to shield them from the blast. Hollie's legs were broken, as was her mother's jaw, and both suffered wounds from shrapnel, including embedded bolts in their bodies, The Guardian reported.
Mr Payton Williams, one of Ms Brewster's friends, said she was a "very smart, funny lady with a heart of gold".
Her partner, Mr Ian Winslow, paid tribute to her on Facebook. "Kelly really was the happiest she has ever been and we had so many things planned together. My daughter Phoebe will be absolutely devastated, like we all are," he said, according to media reports.
REUTERS, AGENCE-FRANCE PRESSE