June 22, 2013 at 11:11 AM ET
They look sleek, sexy and dapper in their 1960s finery, but the cast of "Mad Men" isn't always so polished. In fact, sometimes when the stars who bring Don Draper, Roger Sterling and the rest of the characters to life aren't playing the roles they're most famous for, they're barely recognizable.
Before you say "so long" to the Sterling Cooper & Partners gang for the season on Sunday night, take a look at our roundup of some of the (not-so-) familiar faces.
Don Draper's made some serious mistakes on "Mad Men" this season, but thankfully, the look on the right isn't one of them. No, that's just John Hamm spoofing old-timey, distasteful comedies in an "Alfie and Abner" skit from a live episode of "30 Rock."
If it looks like Roger Sterling has seen better days in the second shot, that's because the actor who plays him, John Slattery, took on the part of a washed up, dirty doctor in the recent return of "Arrested Development."
Peggy Olson's grown into quite the copywriter at Sterling Cooper & Partners, but way before that, actress Elisabeth Moss hit the small screen when she was still small. She made her first appearance in the quirky dramedy "Picket Fences" in 1992.
Even Pete Campbell -- or rather Vincent Kartheiser -- had a fresh-faced look on TV back in the day. Long before joining "Mad Men," Kartheiser played Connor, the non-vamp son of the fang-bearing lead, on "Angel."
If you're a fan of Joan Harris' just-so hair, tailored dresses and crimson lipstick, then Christina Hendricks' turn on "Firefly" might not interest you. But if you want to see Hendricks' range (and don't mind seeing her in far fewer clothes), then be sure to catch both of her decade-old episodes.
Yikes! Megan Draper goes from Don's secretary to wife on "Mad Men," but actress Jessica Pare went from alive to undead in the movie "Suck."
When actress Alison Brie isn't playing the part of Pete's long-suffering wife, Trudy Campbell, she's laughing it up as the brainy and beautiful Annie on the sitcom "Community."
Rest in peace, Lane Pryce. Fans of the fallen character can see actor Jared Harris back in action in the 2011 film "Sherlock Holmes: A Game of Shadows," playing the ultimate match for the sleuth -- the devious Professor Moriarty.
The season six finale of "Mad Men" airs Sunday at 10 p.m. on AMC.