Well never quite understand 'Mad Men' star Jon Hamm's propensity to debase himself in any comedy imaginable, but boy are we thankful for it.  The fabled Don Draper will once again grace the halls of Adult Swim's absurdist medical drama 'Childrens Hospital,' but this time with a twist.  What lured Hamm back to the series, and what's the shocking story behind his cunning mustache?

Thanks to Entertainment Weekly, we've learned that likeable everyman 'Mad Men' star Jon Hamm will once again grace the cast of 'Adult Swim's 'Childrens' Hospital in the upcoming season.  Hamm has previously guested in season past as Derrick Childrens, son of the titular hospital's founder Arthur Childrens.  The twist however, is that this time Hamm will be playing Arthur Childrens himself in flashback, complete with mustache!

Hamm will appear in upcoming episode "Attention Staff," in which Dr. Blake Downs (Rob Corddry) and Dr. Owen Maestro (Rob Huebel) attempt to learn the secret identity behind the hospital's PA announcer (voiced, and potentially played by Michael Cera), whom they've never seen.  The investigation leads the pair to flash back to the 1930s, where Arthur Childrens may or may not have killed an orphan whose ghost haunts the hospital via PA.

Says series creator and executive producer Rob Corddry of the below photo and working with Hamm, "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.”  'Childrens Hospital' begins airing its fourth season August 9.

What say you?  Do period pieces only go so far for highlighting Jon Hamm's handsomeness?  Check out hte below photo, and tell us in the comments if you'll catch Hamm's latest appearance on 'Childrens Hospital!'

Childrens Hospital Season 4 Jon Hamm