Liza Minnelli -- Rehab's in My Rear View ... I'm Headed Back to Work! (VIDEO)

Liza Minnelli is feeling so good since her stint in rehab, she's going back to work.

The legendary star of the stage and screen was leaving her new favorite place -- Lisa Vanderpump's PUMP -- Wednesday night and could not have been nicer chatting up our photog.

Liza revealed she's rehearsing for her next gig -- but didn't say what.