The actress will star in the ABC comedy as the mother of Ellie (Christa Miller), TV Line reports.
A source has revealed that Blakely's character Claire is an "upscale, attractive patrician".
Ellie warns that her mother is a "horrible person" but her friends don't initially understand what she is talking about.
Blakely has previously guest starred in shows including Southland, Men of a Certain Age, Brothers & Sisters and Two and a Half Men.
Scrubs star Sarah Chalke recently signed up for a recurring role in Cougar Town, which will return with new episodes in midseason.