George Clooney is selling his tequila company Casamigos to Diageo for as much as $1 billion, the company said Wednesday.

"If you asked us four years ago if we had a billion dollar company, I don't think we would have said yes," Clooney told CNBC via email. "This reflects Diageo's belief in our company and our belief in Diageo. But we're not going anywhere. We'll still be very much a part of Casamigos. Starting with a shot tonight. Maybe two."

Diageo said it will initially pay $700 million, with the potential for another $300 million based on the tequila's performance over 10 years. The transaction is expected to close during the second half of 2017.

Diageo doesn't expect the deal to add to its earnings until its fourth year. In the first three years, the brand will not have any impact on earnings

Clooney and co-owners Rande Gerber and Michael Meldman are expected to stay with the company after its acquisition.

Gerber founded nightlife companies Midnight Oil and the Gerber Group, and Meldman is a real estate tycoon.

Casamigos, which translates to "house of friends," started as a private collection of tequilas meant just for Gerber and Clooney's friends and family. However, in 2013, the team brought the label public when they had to get licensed to continue making the tequila.

"It immediately took off," Gerber told CNBC in November. "Right now, we're the fastest growing ultra-premium tequila in the country."

— CNBC's Jen Zweben contributed to this report.

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