In a second pic, the actress posed with a few of her girlfriends at a pal's wedding. "2 sets of sister-friends, 23 years strong. Jersey got married in yellow," she posted with the photo.
The blonde color and bowl cut is definitely a cute change for the 28-year-old -- maybe she got her hair inspiration from Sia? The two performed the singer's hit single "Chandelier" on "Jimmy Kimmel Live" earlier this year.
Dunham also took part in the ALS Ice Bucket Challenge on Sunday, and nominated her "Girls" costars Allison Williams, Zosia Mamet and Andrew Rannells. "They got me with that Ice Bucket Challenge," she captioned the video.