General Motors is putting worldwide advertising for Chevrolet in the hands of a new agency, Commonwealth, a 50/50 joint venture between San Francisco-based Goodby, Silverstein & Partners and New York-based McCann Erickson Worldwide.

Until now, Goodby has led Chevrolet’s advertising in the U.S. and McCann has operated as the brand’s agency in a number of global markets, including Mexico, Canada, Brazil, India, Japan, China and Latin America. Previously, Chevrolet used 70 global agencies to handle its advertising.

Chevrolet creative work will continue to be managed by local agencies in China, India and Uzbekistan, GM says.

“This is the first time that two large marketing communications holding companies have come together to form a single company,” GM Vice President and Global Chief Marketing Officer Joel Ewanick says in a statement. “Commonwealth will be based right here in Detroit, and its only focus will be on strengthening and growing Chevrolet into an iconic global brand.”

The latest move comes on top of GM’s recent selection of Carat to be its single agency for media planning and buying. Combined, the two consolidations will save GM $2 billion over the next five years, Ewanick says.

Commonwealth will be dedicated to serving Chevrolet and will be overseen by an 8-person advisory board. Assignments will be doled out to global hubs in Detroit, Milan, Mumbai and Sao Paulo.

Jeff Goodby, co-chairman and creative director of Goodby, Silverstein & Partners, will serve as chairman of the JV.