Housing association Grand Union will take the entire first floor of the refurbished 40,000 sq ft K2 building on a 10-year lease at a headline rent after incentives of £17.50 per sq ft or £352,625 per annum.
There will be a five-year rent review in line with inflation as measured by the Consumer Price Index, with a minimum compound increase of 1% per annum and a maximum increase of 4% per annum.
The rent exceeds the building's current estimated rental value and increases the rental tone for the business Park, Circle said.
Kents Hill Park was acquired by Circle in December 2013 and comprises offices and a conference facility.
Six of the buildings are let to caterer Compass Group on a 25-year lease, ending 2041.
John Arnold, chief executive, said: "This latest letting at Kents Hill further underlines our ability to create shareholder value by acquiring and asset managing well-located buildings through a range of repurposing, lease regearing and redevelopment initiatives.
“With both K1 and K2 and Kents Hill now let to a range of clients on long leases we have created an institutional quality asset and we look forward to the full occupancy being reflected in our next portfolio valuation.”