Sometime early next year, a new building will start climbing for the stars in South Bethlehem, at the South Third and New streets intersection.

Developer Dennis Benner, who is also a Bethlehem attorney, unveiled plans for a $20 million six-story office building that will house two very important tenants - St. Luke’s University Health Network and Lehigh University.

The ground floor of the 125,000-square-foot building, which will be linked to a new four-level parking garage, will consist of retail, with the remaining floors being occupied for office use.

St. Luke’s will occupy at least one floor for clinical, teaching and administrative space. Lehigh University will move 140 employees from its Office of Advancement into the Greenway Building.

Construction is expected to start in the spring and last a year.

]Benner made the announcement recently from inside a tent set up at the vacant lot upon which he will start construction. A crowd of over 100 interested people spilled out around the perimeters. They included a panoply of business leaders like Mike Perrucci, Lehigh Valley Economic Development Corp. CEO Don Cunningham, Bethlehem Mayor Bob Donchez and other city officials, St. Luke’s President Richard Anderson, Lehigh University President John Simon and a host of Lehigh engineering and business students.

Donchez called the building a “major commitment to the future vitality of the South Side.” Over the past several months, he has been engaged in what has been jokingly called “shuttle diplomacy” as he helped put together a deal with two major anchor tenants. Instead of being greeted by a vacant tract, visitors will now see the Greenway Building

Donchez, who grew up on the South Side, calls the building a “catalyst for additional development in South Bethlehem. It will also serve as a gateway into the City from Route 378 and provide much needed foot traffic for the businesses in South Bethlehem.”

Benner, himself, has been a catalyst for in-city development. He has also proposed a nine-story building at Fourth and Vine. He said he is thrilled by the building design prepared by architect Howard Kulp, which includes energy efficient glass, sunscreens and other energy efficiencies.

St. Luke’s President Richard Anderson said its presence demonstates the hospital’s “long standing commitment to our neighbors and the Bethlehem Southside ... .” Lehigh University President John Simon said Lehigh is “proud to play a significant role in this gateway initiative for Southside Bethlehem.”