Hastings Hotels has bought Windsor House in Belfast's Bedford Street for £6.5m in order to convert it into a hotel.
Windsor House, the construction of which was completed in 1974, is one of the tallest buildings in Ireland.
Hastings Hotels, which runs six four- and five-star hotels in Northern Ireland, including Stormont hotel and the Europa hotel in Belfast, said it expected planning permission for a hotel of international quality to be submitted within the next few weeks.
Belfast architects WDR & RT Taggarts have been hired to develop the designs.
The hotel is expected to create 150 hospitality jobs when it opens and Hastings Hotels said it hoped it would help to meet demand from both business and leisure customers in the city.
In a statement, the directors of the company said: "With our philosophy of continuous reinvestment, Hastings Hotels will also continue to extend, enhance and invest in its existing six Northern Ireland hotels, and in the Merrion Hotel in Dublin."