Lena Dunham invited co-star Allison Williams over to her house in Brooklyn to celebrate the end of their show Girls on Sunday night (16Apr17).

Sunday's episode saw the drama series conclude after six seasons and, to mark the occasion, Allison headed over to Lena's house in Brooklyn to watch the finale on her couch, like they did for the series premiere in 2012.

Sharing a selfie of the duo snuggling up on Instagram, Allison wrote, "And that's a wrap on GIRLS. We watched together in Brooklyn, with Manhattan in the background, on a couch, much like it all began. I love you @lenadunham..."

She then went on to thank producers Jenni Konner and Judd Apatow and her co-stars Zosia Mamet, Andrew Rannells, Adam Driver and Ebon Moss-Bachrach, who played her ex-husband Desi. Those members of the cast, alongside Jemima Kirke, were notably absent from the finale episode, which focused on Allison's Marnie and Lena's Hannah trying to raise Hannah's baby together in upstate New York.

"I don't know how to put this into words! #GIRLS #GoodbyeFriend," she concluded.

Lena shared a similar selfie on Instagram and added, "She hath arrived... the final countdown."

Earlier that day, she had shared a bunch of throwback snaps taken six years ago behind-the-scenes of Girls.

The characters' storylines had wrapped up in the penultimate episode, with Zosia's Shoshanna declaring she doesn't want to be friends with them anymore, Hannah and Jemima's character Jessa burying the hatchet, and Hannah moving out of the city for a teaching job.

Lena previously explained to Rolling Stone the last-ever episode would serve as more of an epilogue for the much-loved series.

“The show’s never been about that traditional connection, where it’s four best friends who just can’t get enough of each other," she explained. "So to do a traditional everybody-gets-their-happy-ending finale didn’t feel right. At the same time, we wanted people to have the satisfaction of closure. I think we found kind of a creative way to do that."