Kylie Jenner: No Billboard's Gonna Copy My Mug

Kylie Jenner's about to tell a fat-burning company to FREEZE ... because it's deceiving unsuspecting consumers into believing its product is the key to her curves.

The billboard surfaced in L.A. over the weekend ... displaying a Kylie wannabe on the fat-freezing ad. Although the model isn't the real McCoy, the M.O. is pretty clear -- make people believe it's her.

The fam has already launched its legal team to put the kibosh on the billboard campaign. Fact is ... they probably have a case because the model is a ringer for Kylie and that's clearly the goal.

We're guessing a few phone calls from her attorneys will do the trick.