Shauna's Pre-Rehab Party -- No Booze, No Bra

6/4/2010 12:45 PM PDT
Just hours before entering "Celebrity Rehab" -- Shauna Sand hit the club scene in Hollywood last night for one last half-naked hurrah.

On her way out of one of the clubs, we asked Shauna why she's seeking Dr. Drew's help ... and her answer ... was almost as transparent as her dress.