Flat 2d image on 3d character.

We have a character that is made out of a galaxy - so im trying to get a flat 2d galaxy texture to appear on the character, and one thats not affected by the model (i dont want any of the texture forming around the characters shape).

I tried a projecter but not only can it not give me anything but a grayscale texture, it also conforms to the body - i was thinking if i could apply a billboard to just a material (kinda like the particle system) and apply that to the character (which is not billboarded).

i almost want it to look like the character is cutout from the scene and you can only see a galaxy "behind" the scene - just a flat 2d ortho texture on a 3d model.

any help would be appreciated -