"Change is good," the 28-year-old captioned the picture while wearing a black and white sweater with the word "Demons" across the front.
Her new 'do is reminiscent of hit pop singer/producer Sia, who recently asked the Girls creator to perform an interpretive dance to her song "Chandelier" for Late Night With Seth Meyers in June.
Though some questioned whether Dunham was simply wearing a wig, she proved that the look was more permanent on Saturday, Aug. 16, posting another photo with her blonde locks at a friend's wedding.
"2 sets of sister-friends, 23 years strong. Jersey got married in yellow <3," she captioned the picture, which showed her tresses parted to the side and pushed back behind her ear.
Season 4 of Dunham's hit HBO show recently wrapped filming. The show's premiere date has not be set yet.