Lena Dunham & Allison Williams: Fun on 'Girls' Set!

Lena Dunham chats on a cell phone while filming season three of Girls on Thursday (April 25) in New York City.

The day before, the 26-year-old actress rocked a colorful dress and a Birthday Bitch hat as she continued to film scenes on set of the hit HBO show with co-stars Allison Williams, Zosia Mamet, and Adam Driver.

PHOTOS: Check out the latest pics of Lena Dunham

“I napped at work and dreamed a new word: grunch,” Lena wrote on her Twitter account. “Grunch is a brunch where all the diners grow emotionally over the course of the meal.”

FYI: Allison is wearing a Milly dress.

15+ pictures inside of Lena Dunham and her co-stars on the set of Girls…