The tallest office building in Brooklyn is being topped out at 495 feet on Thursday.

One Willoughby Square, aka 1WSQ, is being developed opposite City Point at Willoughby and Duffield streets by JEMB’s Morris Bailey and Joe Jerome.

As BTB first reported in 2017, its architect, now known as FXCollaborative, loved the project so much it will be moving to 40,000 square feet at the 34-story building. Its space will have an outdoor roof deck that serves as the roof of a new school in its base.

FX design partner Dan Kaplan calls it an “industrial loft for the 21st century.”

A Newmark Knight Frank team of David Falk, Eric Cagner, Whitten Morris, Ryan Gessin and Joseph Sipala is handling office leasing.