Matt Hamilton's famous locks are no more -- the U.S. curling legend just chopped them off ... but, don't worry, he got the cut for a VERY good cause!!
TMZ Sports has learned ... Hamilton -- who won a gold medal at the 2018 Winter Olympics -- hit up a Great Clips salon in Madison, Wisc. on Friday in order to cut his luscious hair and donate it to kids who have experienced hair loss due to medical issues.
It's a sizeable donation from Hamilton .