Clooney, who owns a villa at Lake Como in Italy, has already appeared in an advertising campaign for Martini. He is reported to be earning £1.89m ($3.2m) for the 30-second ad.
The spot, which was shot in Montreal, opens with Clooney walking into a party full of glamorous models. He notices that everyone is drinking boring drinks and demands a glass of Martini spumante. In Italy, 70% of the spumante market consists of women.
The party then livens up and and the spot finishes with the endline "No Martini, no party", which was also used in Clooney's previous work for the brand, created by the Italian agency Armando Testa.
Martini has a long history of advertising with celebrities in its native market of Italy, with Hollywood stars Gwyneth Paltrow and Sharon Stone appearing in ads for the drink, as well as Naomi Campbell.
Clooney is also no stranger to the commercial world, having endorsed products such as Police sunglasses, menswear label Emidio Tucci, and the whisky brand Lancelot.
Like Ben Affleck, who appeared in a much derided advertising campaign for L'Oreal shampoo in Europe this year, Clooney has an agreement with Martini that the ad will not be shown in the US.
As well as appearing in hit films such as 'Ocean's 11' and 'The Perfect Storm', he is producing a new television programme called 'K Street', which takes a wry look at the world of Washington lobbyists, with an innovative mix of people playing themselves and fictional situations.
His current movie is the new Cohen brothers film 'Intolerable Cruelty'.
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