Legendary entertainer Liza Minnelli is undergoing treatment for substance abuse at an undisclosed facility.

The "Cabaret" star, who is known to have suffered from alcohol and drug addictions, has checked herself into a rehab facility, The Associated Press reported.

Minnelli spokesman Scott Gorenstein reassured fans that the 69-year-old was doing well.

"Minnelli has valiantly battled substance abuse over the years, and whenever she has needed to seek treatment, she has done so," Gorenstein noted. "She is currently making excellent progress," he added.

The star is one of the few artists have won an Oscar, a Tony, an Emmy and a Grammy, the AP noted. In September, she underwent back surgery to help heal an injury that had prevented her from performing most of the year; Minnelli had also been unable to attend the New York funeral of comedian and actress Joan Rivers, a good friend.

"I couldn't go to Joan Rivers' funeral, which I desperately wanted to because I loved her," she noted at the time, according to the Daily Mail. "I broke my lower back. Remember a few years ago I was in a wheelchair because I had trouble with my spine? They operated on it then. Well, now, again. They'll have to fuse it," Minnelli added.

The showbiz legend opened up about her battle with alcohol abuse in a 2009 interview with NBC's "Dateline," the New York Daily News recalled.

"I mean, get away from the influence for a minute and you know you have a choice," she explained at the time. "And here are the good things about it: This is a huge thing, this disease, but you can fight it with information and with clarity," Minnelli added.

The actress and singer last sought treatment in 2004, Us Weekly recalled. In 2010, she turned down a $500,000 offer to appear on "Celebrity Rehab," a VH1 reality TV show in which Drew Pinsky treated a group of people for alcohol and drug addiction.

"Liza Minnelli is not now, nor will ever be, on 'Celebrity Rehab,'" a spokesman had told the magazine at the time.