Ingenhoven and Architectus have won the international design competition for the mixed-use tower at 505-523 George Street, owned by Mirvac and Coombes Property Group.

Developers Mirvac and Coombes Property have appointed architects Ingenhoven and Architectus to design Sydney's newest $1 billion residential skyscraper.

Sitting atop the Event cinemas at 505-523 George Street, the 80-storey tower will have apartments, several levels of retail, two childcare centres and a community meeting room with active shopfronts and outdoor dining spilling out to the George Street pedestrian boulevard.

The tower will rise 270 metres above ground including a 10 metre roof feature, making it one of the tallest in the area.

According to Event Cinemas, the property is subject to a long lease with the owners. It is expected they will remain open while the developers work through the necessary approvals for the project.