An IT company from Down Under has signed the lease for one of the top floors at One World Trade Center Tuesday.

Servcorp, which specializes in virtual offices and online infrastructure, will move into its 34,775-square-foot space on the 85th floor in early 2015, according to the real estate group Durst Organization, which signed the lease.

The Australia-based company's deal means that One World Trade Center will be 57.5% occupied.

Its main tenant, Condé Nast, is set to move into the tallest building in the Western Hemisphere in late fall.

Other tenants include the U.S. government, advertising firm KiDS Creative LLC, China Center New York LLC, a London-based investment company BMB Group, and Legends Hospitality, which will manage the tower's observation deck.