The comedy, which is based on the British show of the same name, focuses on two PR executives with a complicated relationship.
TV Guide reports that Hahn will play one of the executives, a woman whose fiancé has recently died.
She will star opposite Hank Azaria, who has already been cast in the other lead role.
Hahn previously played Lily in Crossing Jordan and has appeared in several episodes of Hung. She has also featured in movies such as Revolutionary Road, Anchorman and How To Lose A Guy In 10 Days.
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