George Clooney may be the face of dozens of films and fancy coffee, but it's in premium tequila that he just hit the real jackpot.

Diageo Plc agreed to acquire fast-growing tequila brand Casamigos, co-founded four years ago by Clooney, for as much as $US1 billion, or about $1.3 billion. The deal expands the London-based distiller's lineup in a fast-growing category, where it already owns the Don Julio, DeLeon and Peligroso brands.

Clooney, the Oscar-winner best known for his role in movies such as Ocean's Eleven and as a pitchman for Nespresso coffee, created Casamigos in 2013 with developer Mike Meldman and entertainment entrepreneur Rande Gerber, who's married to model Cindy Crawford. The tequila is made by an undisclosed partner in Mexico.

Diageo and its rivals have been expanding their lineups of tequila and mezcal, which is also produced from the agave plant. Pernod Ricard SA this month agreed to acquire the Del Maguey mezcal brand, following a distribution agreement by Diageo with Mezcal Union signed in February 2016.