Linda Sawyer, the chief executive of the agency, said that the pair were both leaving to pursue other interests.
She also confirmed that a shortlist of replacements has been drawn up, but appointments will not be made until the new year.
Delaney joined the agency 13 years ago. In 2001, she was named as the managing partner and executive creative director at Deutsch. Last year, she was named as the chief creative of the New York office.
She joined the agency from TBWA\Chiat\Day in New York, where she was an associate creative director.