The design team for the huge Ministry of Defence scheme in South Wales will include HLM, Scott Brownrigg and Capita Architecture.
Earlier this year the Secretary of State for Defence, Des Browne, announced that the consortium had been chosen as the preferred bidder for the huge 'Package One contract' and also as provisional preferred bidder for the 'Package Two contract' under the Government's Defence Training Review (DTR) Rationalisation programme.
The appointment means the team will now start working on delivering a giant joint training centre for the Army, Royal Navy and the Royal Air Force.
The facility will feature accommodation, offices and training facilities across the vast site.
Describing Metrix's approach to the project, a spokesman for the consortium said: 'St Athan already has an excellent infrastructure in place that provides, in my opinion, a fine basis for the creation of a world-class military training environment.
'It will attract the single biggest ever investment in Wales and would create 4,000 jobs on site and a further 1,500 jobs off site.'