Girls will be girls.

Lena Dunham served as a bridesmaid at her best friend Isabel Bramlette Halley's wedding on Saturday, June 28. The "Girls" star, 28, wore a cap sleeved grey dress, which featured a low-back, by Reformation and sported a chic, braided 'do. She deemed the gown " charming, breathable and stylish."

Getting ready for my best friend's wedding. Potent, emotional, feel someone should make a movie about it. Called "Wedding Of My Best Friend"

- Lena Dunham (@lenadunham) June 27, 2014

"Isabel and I met 28 years ago," Dunham wrote on Instagram alongside the below photo. "Watching her take this step was a crazy honor."

The event looks to have taken place somewhere in the country -- the wooded background sort of, kind of gives it away.