Abstract: A multi-chambered container assembly including a two-piece adapter having a base and a hollow member that cooperate to open and close a passage between a first chamber provided by a bottle and a second chamber formed in the hollow member. The base defines a first opening and has a substantially semi-spherical concave wall surrounding the first opening, and the hollow member includes a substantially semi-spherical convex wall that pivotally (slidably) fits within the concave wall of the base. The hollow member is snap-coupled to the base using a pair of pins and a pair of cam grooves that facilitate movement of the hollow member between a closed (first) position and an open (second) position. The base can be integrally formed onto the bottle to provide a two-piece multi-chambered container.