The actor - who plays Don Draper in the series - has revealed that he quietly sought treatment at a facility earlier this year, completing a 30-day programme.
A statement said: "With the support of his longtime partner Jennifer Westfeldt, Jon Hamm recently completed treatment for his struggle with alcohol addiction. They have asked for privacy and sensitivity going forward."
No further details were provided.
Jon, 44, released the statement ahead of the new series of Mad Men - its last series - premiering this spring. He plays advertising exec Don Draper, who has alcohol battles of his own.
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