Foster + Partners is working on a new smart city design with actor Idris Elba for a coastal island off the shores of Sierra Leone. The news was reported by the BBC on Sunday, when the plan was revealed for the first time after five years of planning. 

Sasaki Associates will collaborate with the firm, Elba, and his business partners at the Sherbro Alliance Partners (or SAP). Their plan is to preserve nature areas on the 230-square-mile Sherbro Island (which has roughly ten times the land area as Manhattan) while enacting a new "eco-city" capable of supporting up to one million residents. 

The outlet reports the project is to be financed through a public-private partnership and that the island will "be designated a special economic zone with a separate legal and economic system from the rest of Sierra Leone." Some online commentators have compared it to Disney World, the crypto-funded Akon City in Senegal, or the new planned community in Northern California that’s backed by a group of tech billionaires. 

Design details from Foster and Sasaki remain unclear. A spokesperson informed the BBC that development will be focused on the existing community of Bonthe (pop. 10,000). Elba also told the outlet that "the character of the island hopefully will remain intact. It's a beautiful, green part of the world, and we don't want to disturb that." 

Construction timelines or costs for the project have not been reported.