Kylie Jenner's put up a billboard smack in the middle of WeHo that kills 2 birds with one stone -- celebrating Stormi's birthday and hawks the kiddo's new makeup collection. The massive bday card -- in a prime location on Santa Monica Blvd -- shows Kylie gently cradling Stormi, who turns 2 on February 1. Obviously NOT coincidentally, Kylie's also adding to her cosmetics empire on that day ...with makeup products inspired by Stormi.