Hotel and resort giant Starwood has agreed a deal to open a 125-room hotel and 220 St. Regis-branded residences in Serbia’s tallest mixed-use tower.

The Kula Belgrade – a 550ft tall and twisting glass skyscraper designed by the Chicago office of architecture firm Skidmore, Owings & Merrill Global – is scheduled to open in 2019, when it will form the centerpiece of a major new waterfront development in the capital Belgrade.

The St. Regis Belgrade hotel will occupy the first nine floors of the building, with rooms looking out either to the historic city or the River Sava. Facilities will also include a destination restaurant at the top of the tower, a St. Regis Bar and a spa, pool and gymnasium.

The wider waterfront development, one of the largest in Europe, is designed as a “modern city within the city” to reinvigorate Belgrade, which was significantly damaged during the Kosovo War in 1999. It will include 1.8 million sq m of shops, hotels, educational institutions, a cultural district and a 2km long public waterfront featuring leisure attractions. The project, reported to be worth €3.5bn (US$4bn, £2.7bn), is being developed by Abu Dhabi-based Eagle Hills and operated by the Belgrade Waterfront LLC.

“The cooperation between Belgrade Waterfront and Starwood with The St. Regis Belgrade is a sign of prosperity for Serbia and its potential as a tourist destination,” said Belgrade Waterfront general manager Nikola Nedeljkovic. “Setting the tone for the waterfront, the St. Regis brand is renowned for providing unmatched services for its guests.”

The Kula Belgrade, which means Belgrade Tower in English, will also feature 220 high-end St. Regis residences of different sizes spread across the 14th and 39th floors.

“This signing fuels Starwood’s strong growth momentum in Europe, where we continue to see a demand for high-end hotel accommodations,” said Karl Bieberach, vice president of development for Starwood’s European, African and Middle Eastern properties. “We are particularly interested in expanding our luxury portfolio and The St. Regis Belgrade will be a terrific addition to our strong and growing footprint in the region.”

Starwood will soon merge with Marriott International after shareholders of both companies voted en masse for the proposed deal. Marriott's cash-and-stock acquisition of Starwood, valued at US$12.41bn, will create the world’s largest hotel company.