Roberta Flack rushed to hospital from Apollo Theater appearance

Singer-songwriter Roberta Flack was under observation at a Manhattan hospital Saturday after suddenly feeling ill before her appearance at Harlem's Apollo Theater.

The 81-year-old Grammy award-winner was taken to Harlem Hospital in an ambulance Friday evening, TMZ reported .

Flack apparently became very dizzy as she was about to receive a lifetime achievement award from The Jazz Foundation of America.

Watch: Roberta Flack's Apollo performance before she was hospitalized

She was in the theater's green room, waiting to go onstage, when she suffered some kind of "episode" those around her feared might have been related to a stroke she suffered two years ago, said Jazz Foundation spokeswoman Bobbi Marcus.

On Saturday, Marcus said she spoke to Flack's manager "and am happy to report that she's doing well."

Flack has been transferred from the Harlem hospital to another Manhattan hospital where she's under the care of her private doctors, Marcus said. "They are keeping her for observation and expect she'll be released in the next couple of days."

Earlier Friday evening, Flack arrived at the Apollo in a wheelchair for red carpet photos, looking "beautiful with hair and makeup," Marcus said.

She was being honored at the foundation's annual benefit concert, called "A Great Night In Harlem."

The show still went on, including a tribute segment to the singer who had gained fame in the 1970s and 1980s with such hit songs as "Killing Me Softly" and "The First Time Ever I Saw Your Face."

Featured performers at the benefit included Cassandra Wilson, Nona Hendryx, and Alabama Shakes' lead singer, Brittany Howard.

Flack's manager, Suzanne Koga, was not immediately available on Saturday.

The mission of the Jazz Foundation of America is to provide emergency support to great jazz and blues musicians who fall on hard times and to preserve their musical legacy.