Dual-purpose container closure

A closure for a beverage container, comprising:

• a body having an attachment interface to engage to a top of a beverage container;
• a sealed, elongated enclosure attached to an underside of the body;
• and
• a single tip-up access element adapted to selectively open and close either a first opening passing through the body into the sealed, elongated enclosure or a second opening passing through the body directly to an inner volume of the beverage container, by a movement of the single tip-up access element.