A rep for Liza told People that she is scheduled to have the surgery this week in New York.
"Minnelli, who has been dancing on stage since she was a teenager, is 63," her rep told the mag. "She is expected to make a full recovery."
The knee surgery will reportedly keep Liza away from the Grammy Awards on January 31 in LA.
The singer is nominated for Best Traditional Pop Vocal Album for the original cast recording of her Tony-winning Broadway show "Liza's at the Palace."
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