Abstract: The present invention relates to closure arrangements for liquid containers, particularly but not exclusively for drinks bottles. A closure arrangement (20) for a liquid container for a base liquid comprises a reservoir (24A, 24B) for an additive liquid (28A, 28B). The closure arrangement (20) comprises a passage (54) for flow of liquid from the base liquid container (11) to a user, the passage including a mixing space (26) for mixing the additive liquid from the reservoir and the base liquid. The present invention further relates to a liquid container assembly including a closure arrangement. The present invention further relates to an additive reservoir for use in a closure arrangement.