What to wear under a large v-neck hoodie?

I have this light green, fleece, v-neck hoodie that my former teacher bought me as a Christmas present, thing is, it's in a large and so the v-neck comes all the way down to my ribs! I don't know what to wear under it, since it's the kind of green that can be easily matched with a dark blue bootbut jean. Please help! I really have no clue how to wear it!