Hyams left his post as design director at Aedas to 'pursue other interests' in September, and at the time described his departure as 'tragic' (Aedas design director Hyams in shock departure).
The practice will also boast Aart Koning, Karsten Huneck, Max Rengifo, and Kate Millen, formerly a partner with engineer Hoare Lea.
Hyams said: 'ASTUDIO brings together experts to enrich our design process, Kate will provide specialist environmental engineering advice to the team throughout the design and at the outset of a project to impact on the concept of the building.
'This will create a more holistic approach to design that will challenge the current industry.'
Hyams was formerly a rising star at Foster & Partners before being poached by Aedas.