The storylines were as gripping as ever. But there was almost as much focus on the fashion as Mad Men returned to screens.
Gone are the nipped in waists, full skirts and pretty pastel shades.
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The female characters instead showcase late Sixties trends, including mini-skirts, geometric prints and monochrome outfits.
The styles placed them perfectly in 1966, where the two-hour season opener began.
Jon Hamm's character, the charismatic Don Draper, has a new wife, Megan, who is on sex kittenish form.
She looked the epitome of Swinging Sixties chic in a stylish black minidress, with her hair in a voluminous bob, as she threw her husband a surprise birthday party.
Even the makeup – heavy black eyeliner and false eyelashes – is reminiscent of the era.
Don's apartment – where Megan gave a raunchy rendition of French song Zoo Bisou Bisou while the party was in full swing – is also pure Sixties, with its white carpet, sunken living room and minimalist furniture.
Meanwhile, guests at the bash – Trudy Campbell and Jane Sterling – both show off glam beehive up dos, made popular by Sixties singer Dusty Springfield.
Even office manager Joan Holloway, played by Christina Hendricks, embraces the more daring style era with a bright fuchsia dress featuring a neckline much lower than she would normally wear.