Constellation Brands of the US agreed to pay Aus$10.5 for each BRL Hardy share, valuing the Adelaide firm at Aus$1.9bn (US$1.1bn; £680m).

Constellation Brands

Paul Masson Nobilo Ravenswood Stowells of Chelsea

BRL Hardy chief executive Stephen Millar will head the combined group.

The companies already run a joint venture, Pacific Wine Partners, which markets the Australian firm's wines in the US.

Ahead of the deal, Constellation chairman Richard Sands said the tie-up would enable the US firm to emphasise the fastest growing category - "new world" wines from the US, Australia, New Zealand and Chile.

BRL Hardy

Banrock Station Stamp of Australia Nottage Hill La Baume

BRL Hardy is Australia's biggest wine company and was formed in 1992 when Berri Renmano joined together with family-owned Thomas Hardy & Sons.

Constellation Brands produces cider and beer as well as wine.

In the UK it owns Matthew Clark, maker of Blackthorn cider.