CHARLIE SHEEN donated $75,000 to help a 10-year-old girl who's fighting cancer, and his stunt double Eddie Braun chipped in $25,000, for a grand total of $100,000.

It all came about because Charlie was talking to a Hermosa Beach Police officer, and in the course of the conversation, the cop mentioned that a fellow cop had a daughter with cancer.

The next day, he and Eddie sent the money to the Hermosa Beach Police Officer's Association.  All the proceeds will go to the family.  (Here's a picture of Charlie's check.)  (E! Online)

The Officer's Association posted a note of thankson their website.