Liza Minnelli has been admitted to a drug and alcohol rehabilitation unit for an eight-week "self-help" programme.
Annual stay: Liza Minnelli
Her publicist, Warren Cowan, said she had gone to the Caron Foundation in rural Pennsylvania two weeks ago.
Minnelli, 57, has spoken openly about being addicted to alcohol and painkillers and about her past stints in rehabilitation programmes.
Last week Minnelli and her husband David Gest suddenly cancelled their planned lavish first wedding anniversary celebrations, citing the war.
They had earlier announced a party at New York's Times Square on 15 April for 1,200 celebrity friends.
Mr Cowan said: "She is in the Caron centre where she is obliged to go for eight weeks every year for a self-help programme.
"She is fine and she will continue her concert tour and all of her commitments as promised. She is in great condition."
Minnelli, who has been married four times, came near death in 2000 after a bout of viral encephalitis.
She relaunched both her career and her personal life with her marriage to producer Gest in March last year.
The couple are currently embroiled in a legal fight over their aborted television reality series.
They were also sued this week by a contractor over allegedly unpaid home repair bills.
New York-based G&I Construction Corp says they owe nearly $138,000 (£87,000) for renovations to their Manhattan apartment.