Signature Living's Crumlin Road Courthouse hotel plans have been approved by Belfast City Council.
The hotel company acquired the property last year for an undisclosed sum and announced plans at the time to invest £25m to transform it into a hotel called the Crum hotel.
Signature Living has now announced plans to invest £15m to transform the property into a 77-bedroom hotel, anticipated to open summer 2019.
The Courthouse was designed by Charles Lanyon and completed in 1850. The site saw hundreds of IRA members jailed during the Troubles and was closed in June 1998 after the signing of the Good Friday Agreement.
It was sold to local investor Barry Gilligan in 2003, who applied for planning permission in 2006 to turn the Grade B-listed building into a 161-bedroom hotel, but the plans never came to fruition. The site suffered a series of fires in 2009 and has been lying derelict since.
Chairman Lawrence Kenwright said: "We are absolutely delighted to have been granted planning permission for the Crumlin Road Courthouse which will allow us to get fully underway with our development plans for the site and start construction.
"The history of the building will become an integral part of the look and feel for the interior with a sense of theatre, something which Signature Living is renowned for in all of its hotels."
Signature Living launched with the opening of its Victoria Street Apartments in Liverpool in 2008 and expanded into hotels with the opening of the Signature Living hotel in 2013 in the city.
The company's hotel portfolio now includes 30 James Street and the Shankly hotel in Liverpool, and the Exchange hotel in Cardiff, with plans to open the Waring and George Best hotels in Belfast by the end of the year.