Abstract: An aspect of the invention provides a container closure for a container comprising a body portion having a first end configured for attachment to a container and a second end configured to allow content of the container to exit the container closure, a reservoir positioned within the body portion between the first and second ends thereof and an actuable seal that is moveable between a first configuration in which the reservoir is sealed and a second configuration in which the actuable seal is moved in the direction of the second end of the body portion to create a gap between the actuable seal and second end of the body portion, wherein the actuable seal is moveable between the first configuration and second configuration by a plunger extending from the first end of the body portion to the second end of the body portion and wherein the actuable seal engages a surface of the reservoir when in the first configuration.