Jon Hamm Jon Hamm

Don Draper will soon be seen wandering the halls of Childrens Hospital.

Jon Hamm is set to guest-star in an upcoming episode of the Adult Swim comedy, playing the hospital's founder, Arthur Childrens, Entertainment Weekly reports.

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The episode, titled "Attention Staff," flashes back to the 1930s as Rob Corddry's Dr. Blake Downs and Rob Huebel's Dr. Owen Maestro try to solve the mystery of the hospital's unidentified PA announcer — rumored to be either the ghost of a child Childrens killed when the facility was an orphanage, or perhaps Childrens himself.

Hamm has previously appeared on the show as Arthur Childrens' son, Derrick.

Season 4 of Childrens Hospital premieres Aug. 9.