The Devil Wears Prada costars hit the Green Door for jazz night, where they reserved a private table complete with bottle service.
After smoking breaks on the patio and chats with friends and Industry types, the two friends decided to sing backup for the house band just before last call.
"They were great," an onlooker tells E! News of their duet. The babes belted out two different songs, including an upbeat number and a sultry tune, before hopping in a chauffeured SUV around 2 a.m.
Good to see their recent breakups aren't getting the best of them.
—Reporting by Matt Donnelly