Liza Minnelli -- Out of Rehab, Hanging at 'Housewives' Haunt

Liza Minnelli has checked out of a Malibu rehab facility, a little more than a month after checking in for treatment for substance abuse.

The "Cabaret" star was seen out Sunday night at PUMP in West Hollywood ... which is owned by "The Real Housewives of Beverly Hills" star Lisa Vanderpump.

According to our spies, Liza arrived with a guy around 7 PM and enjoyed dinner. We're told she was laughing, having a good time, and was very cordial with fans.

Our sources say she stayed until around 9 PM. She was not intoxicated in any way.