Michael Showalter -- whose credits include The Big Sick and The Lovebirds -- is directing the eight-episode limited series, which is inspired by real events.
Rudd will play "psychiatrist to the stars" Dr. Ike Herschkopf and Ferrell will play his longtime patient Marty Markowitz.
"Over the course of their relationship, the all-too-charming Ike slowly takes over Marty's life, even moving into Marty's Hamptons home and taking over his family business," a press release said. "The series explores how a seemingly normal doctor-patient dynamic morphs into an unprecedentedly exploitative relationship filled with manipulation, power grabs and dysfunction at its finest."
No start date for production has been announced yet.