Character Mesh As Alpha Cutout

So I want to basically project a texture onto my character, but I don’t want that texture to form to the mesh of my character. The only other way I could think to achieve this is rendering the character model to a flat image in real-time and project a texture onto that flat image, but I think that would be too expensive for this project.

Is there a way to have a camera facing plane with my texture, and use my real-time character model as the alpha somehow?