UK studio Foster + Partners is reportedly designing a two-kilometre-high skyscraper in Riyadh, Saudi Arabia, which if completed would be the world's tallest building.

According to a report in UK architecture magazine Architects' Journal (AJ), the UK studio is designing the megatall skyscraper for a site to the north of the Saudi capital.

The AJ reports that the skyscraper will be located near the city's international airport, which is currently being redeveloped by Foster + Partners.

Skyscraper would be world's tallest building

If built, the skyscraper would become the world's tallest building, being over twice the height of the current record holder, the 828-metre-high Burj Khalifa in Dubai, United Arab Emirates.

The building would also become the tallest building in Saudi Arabia, overtaking the 600-metre-high Abraj Al Bait Royal Clock Tower in Mecca.

The proposal would be Saudi Arabia's second prominent attempt to build the world's tallest building. Designed by Adrian Smith + Gill Gordon Architecture, the 1,000-metre-high Jeddah Tower is currently under construction in Jeddah.

The first images of the prospective tower were released in 2011, with construction starting shortly after in 2013. However, the project has been on hold and only restarted last year.

Saudi Arabia is currently undertaking a huge number of architectural projects that it has termed "giga projects". These include the 170-kilometre-long city called The Line, which itself is planned to rise to 500 metres and which will be one of the country's tallest buildings.

The Line forms part of the Neom project, which has been criticised by the United Nation's Human Rights Council.

Foster + Partners designing numerous projects in Saudi

Foster + Partners has completed numerous projects in Saudi Arabia, including the Al Faisaliah Tower that when completed in 2000 was the country's tallest building. In 2019, a quartet of high-speed rail stations designed by the studio opened.

Along with the megatall skyscraper and the Riyadh airport, the studio is working on two other airports. Construction has begun on its Red Sea International Airport, while it is also designing a private airport terminal and control tower for a luxury resort on the Red Sea coast.

The studio is also designing a hotel and "the world's first fully immersive experiential marine life centre" at the resort.

Foster + Partners has been approached for comment.

The main photo, which shows Riyadh, is by Tom Ravenscroft.