Property developer Qatari Diar has announced the appointment of Rosewood Hotels & Resorts as the operator for a new hotel opening within London’s former US Embassy building in Grosvenor Square.

The selection follows a lengthy process in which a series of international hotel companies submitted proposals for how they would run an “ambitious world-class hotel, retail and event space” with 137 bedrooms, five restaurants, six flagship retail units, a spa and a 1,000 capacity ballroom.

The embassy building was originally designed by Finnish-American architect Eero Saarinen and has become a landmark, gaining grade II listed status in 2009. In November last year, a proposal to renovate the building by David Chipperfield won planning permission, subject to the building retaining its most iconic elements, including the large gilded aluminium eagle on the roof.

Over the coming months, Qatari Diar will work closely with Rosewood Hotels & Resorts and Chipperfield on the final design, ahead of the embassy staff moving into their new home in Nine Elms later this year.

Sheikh Jassim Al-Thani, chief development officer of the company’s Europe & Americas division, said: “We are delighted to welcome Rosewood Hotels & Resorts on-board with this exciting re-development. This is a major opportunity for London and a hotel of this exceptional calibre perfectly aligns with our vision and ambition to renew the heart of Mayfair and cement the neighbourhood’s unique character as the leading hospitality, arts and luxury retail quarter in London for residents and visitors to enjoy.”

Qatari Diar’s plans for the site also include significant enhancements to Grosvenor Square, including the removal of the existing security bollards and barricades to provide additional pedestrian walkways.

In a statement, the company said: “Working alongside the Grosvenor Estate, these works will support Qatari Diar’s further public realm improvements to restore Grosvenor Square as an open, expansive green space fitting for one of London’s most prominent and established gardens."