The 200-plus room luxury venue could be built in Knightsbridge, west London, near the iconic Harrods store.
Among options under consideration is whether to convert office space or an old hotel into a £300million-plus site, the Dailymail reports.
He opened his first hotel in Dubai in collaboration with Emaar Properties in April last year and has a hotel in Milan.
The two companies are working together on possible expansion in Paris, New York, Tokyo and Shanghai.
Armani is responsible for overseeing all aspects of the interior design and style of the hotels. Dubai-based Emaar Properties is responsible for construction.