Power trio alert!

Following Beyoncé's concert at the Barclays Center on Saturday night, the songstress, hubby Jay Z and pal Justin Timberlake continued the party at the laid-back bar Woodwork in Prospect Heights, dished a spy. The group arrived around 1 a.m. and was very "casual and chill," said the witness.

"They seemed to just want to hang out and unwind," said the spy.

Beyoncé also rocked Brooklyn's Barclays on Sunday night and on Monday evening, when she was joined on stage by her man for a surprise two-song performance. Jay Z and Timberlake are touring together on their Legends of the Summer tour, which ends Aug. 16.