A beverage container assembly for use with a blender is provided comprising a beverage container having an open top portion and a closed bottom portion. A first removable cover is for selectively covering the top portion of the beverage container. The first cover is adapted to be removably mountable on and off a blender and comprises an adapter portion for mounting the beverage container on a blender. A second removable cover is for selectively covering the open top portion of the beverage container. The second cover includes a drinking hole. The first and second covers are interchangeable on the beverage container and the second cover is mountable on the closed bottom portion for storage.