Clark was previously the president and chief executive of DDB Worldwide North America. Brymer, who has led DDB for 12 years, is becoming chairman of the Omnicom-owned network.
Clark joined DDB Worldwide in January 2016 to lead its 17 offices and 2000 people across North America and Canada after an eight-year career at Coca-Cola North America where she rose to president, sparkling brands and strategic marketing. She is also a former senior vice-president, global advertising, at AT&T.
Brymer became DDB Worldwide’s global chief executive in 2006. He joined BBDO in 1982 to open and run its Houston office before joining Interbrand in 1985. Following its acquisition by Omnicom in 1993 he was made president and chief executive of the branding firm.
DDB was unable to immediately respond to a request for comment.
Update (1:25 pm GMT): DDB has confirmed Clark and Brymer's appointments in a statement. Clark's promotion to president and chief executive of DDB Worldwide is effective immediately.
John Wren, president and chief executive of Omnicom, added: "During his tenure as chief executive of DDB, Chuck has successfully grown DDB as not only one of the most creative agencies in the advertising industry but also a leading network for CRM, retail activation, branding, and digital services around the globe."
He continued: "At Omnicom, we recognise the importance of succession planning, and Chuck and I knew that Wendy would be the right person to take the helm of DDB. Her experience leading DDB North America coupled with her expertise as a leading marketer makes this a seamless leadership transition that will build upon DDB's capabilities and reputation as a leader in the business."