Chris Brown I'll Take Those Panties

6/23/2013 1:10 PM PDT

When Chris Brown sings, the panties start dropping ... and TMZ has the footage to prove it.

Chris was performing at Heat Nightclub in Anaheim Saturday ... when a very generous female fan handed the singer a silky white thong as a present.

Unclear, from the footage, if it was used or not -- but witnesses on scene tell us the club was super hot and sweaty, sooooo ...
Watch Chris' reaction to the gifted panty -- he's definitely NOT a germaphobe.