By Dan Snierson
Updated July 24, 2012 at 10:39 PM EDT
Credit: Darren Michaels

Jon Hamm is traveling back in time again, though not to the ’60s. EW has learned that the Mad Men actor will guest star in an upcoming episode of the Adult Swim comedy Childrens Hospital, playing the institution’s founder, Arthur Childrens, in several ’30s-era flashbacks. In the episode, titled “Attention Staff,” Dr. Blake Downs (Rob Corddry) and Dr. Owen Maestro (Rob Huebel) attempt to uncover the identity of the never-seen P.A. announcer (voiced again by Michael Cera, who may or may not appear in the episode). Is there truth to the rumor that it’s actually the ghost of a child that was killed by Childrens back when the hospital used to be an orphanage? Or better yet, could it possibly be… Arthur Childrens himself? Nope. Now you’re just talking crazy.

Scroll down for a preview of the mustachioed retro-Hamm conferring off-camera with creator/executive producer Corddry, who sent us this description of the action: “In this picture, I’m probably giving him handsome lessons… Working with Jon is as pleasant as you would imagine. However, the women on set tend to put a little extra effort into their morning beauty routines. Lots of extra rouge, teeth whitening, bows in the hair, etc.” You can also check out a photo of Hamm with series star Ken Marino, who is exercising admirable restraint by not staring directly into the face of Hamm heaven.

Hamm is no stranger to the halls of Childrens Hospital: He popped up as Arthur’s son, Derrick, in seasons 2 and 3. “Attention Staff” will air during the show’s fourth season, which begins Aug. 9.

Childrens Hospital was nominated for an Emmy in the Short-Format Live-Action category last week, while Hamm received his fifth Lead Actor in Drama nomination for Mad Men, as well as his third Guest Actor in a Comedy nod for 30 Rock.

Credit: Lewis Jacobs/NBC
Credit: Lewis Jacobs/NBC

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