The current site was built in 1969 and provides 1,250 beds.
The university has committed to closing existing accommodation this year with plans to start demolition work in the summer.
The redevelopment will cost £250m with main construction work expected to start early in 2025.
Joe Lister, Unite Students Chief Executive Officer, said: “Partnering with Newcastle University to redevelop Castle Leazes and deliver 2,000 beds of high-quality, affordable accommodation for students is a hugely exciting step for Unite Students.
“The partnership will provide further support to Newcastle University in meeting their accommodation needs at a time of real housing shortage, so that they can focus on providing a world-class experience for their students.”