Phyllis McGuire, Last of a Singing Sisters Act, Dies at 89 Starting in the ’50s, the McGuire Sisters were one of America’s most popular vocal groups, their three-part harmonies a balm to audiences rattled by rock ’n’ roll. The McGuire Sisters in 1953 — from left, Christine, Phyllis and Dorothy. They became staples of television variety shows.Credit...Associated Press Dec. 31, 2020 Phyllis McGuire, the lead singer and last surviving member of the McGuire Sisters, who bewitched teenage America in the 1950s with chart-topping renditions of “Sincerely” and “Sugartime” in a sweet, innocent harmony that went with car fins, charm bracelets and duck-tail haircuts, died on Tuesday at her home in Las Vegas. She was 89.