The actress will be starring in the ABC comedy opposite Rob Corddry, who plays a father who joins the secret service in order to prove himself to his highly intelligent son.
Brewster's is portraying the ex-wife of Tim (Corddry) and the mother of his son Marcus (Mason Cook).
Her character has been described as a cold, difficult woman who is a devotee of psychological therapy.
Brewster has worked extensively in television, with memorable roles including a six-episode arc in Friends, regular roles in Huff and Criminal Minds, and a recent guest appearance in Modern Family.
The American remake of Spy is being produced by Hat Trick Productions and Simeon Goulden, who created the original British series.
Spy has run for two series on Sky 1 in the UK and stars Darren Boyd, Jude Wright and Dolly Wells.