Picking the perfect Halloween costume can be daunting, can't it? Well, let us be the first to say that the easiest way to come up with an outfit is look to your favorite celebrities. These five ladies in the spotlight will be easy to emulate this Halloween, whether you're a watercolor woman à la Lady Gaga or revel in retro beauty like Lana Del Rey. Plus, shop the necessities for each look below. On Kirbie: H&M top.