The news, accompanied by a single teaser of image of the CX-8's interior, marks the first Japanese-market availability of a three-row Mazda SUV.
Most details are still to come, although the company has revealed a few key figures including size, seating capacity and engine.
The CX-8 will be offered in six- and seven-seat forms, riding on the same 2930mm wheelbase that underpins the CX-9 available locally.
The shared wheelbase length suggests this new model will boast a coupe-inspired exterior, making it a companion to the CX-9 in the same way the overseas CX-4 - revealed this time last year - sits alongside the popular CX-5.
Above: the CX-4, offered only in select overseas markets
Although the CX-8 and CX-9 will share an identical footprint, the CX-8 will be shorter overall: 4900mm to the CX-9's 5075mm. It will also be notably narrower (1840mm to 1969mm) and not quite as tall (1730mm to 1747mm).
This suggests that although the CX-8 will likely be more of a lifestyle-oriented option, rear passengers - if only the second row - will not suffer greatly for comfort.
Unlike the petrol-only CX-9, the CX-8 will be offered with Mazda's twin-turbo 2.2-litre diesel engine, which, locally, offers 129kW and 420Nm of torque. This will be matched to the company's six-speed SkyActiv automatic transmission.
Australian buyers will have to stick with CX-3, CX-5 and CX-9 if they're in the market for a Mazda-badged SUV - although the company's local arm is at least interested in the new model.
The new Mazda CX-8 has been announced in Japan today. It is currently planned for production and launch in Japan only," Mazda Australia communications manager Karla Leach told CarAdvice today.
"We currently have CX-5 and CX-9 that offer both five- and seven-seat SUV options in Australia, which are both enjoying great popularity with Australian consumers.
"If plans evolve and it is offered globally, Mazda Australia would be keen to assess its viability in this market."