Idris Elba wants to build an eco-friendly smart city in Sierra Leone.

The 51-year-old star is working with Siaka Stevens, his childhood friend, to develop a smart city on Sherbro Island, after the region was given autonomy by the government of Sierra Leone in order to allow the construction work to go ahead.

Speaking to the BBC, Idris shared: "Originally we went there thinking how could we bring tourism to the most incredible 19 miles of beachfront."

Idris hopes to help install wind-powered renewable electricity in Sierra Leone for the first time.

And the actor admits that it's a highly ambitious project.

The London-born star said: "It's a dream, you know, but I work in the make-believe business.

"It's about being self-reliant, it's about bringing an economy that feeds itself and has growth potential. I'm very keen to reframe the way Africa is viewed … as an aid model.

"This opportunity is completely different."

Idris' dad was born in Sierra Leone and this project means a huge amount to him, adding that he's "qualified to dream big".

He shared: "Part of me wants to build that beautiful retirement home for my mum.

"Never in my lifetime would I have thought I could build the foundation for a new smart-city ... I'm not qualified for that. But I am qualified to dream big."

Idris also revealed that he'll be following his dad's advice during the project.

The actor - who has previously starred in hit TV shows such as 'The Wire' and 'Luther' - said: "If you're going to do it, make sure you do it properly.

"You do it good, you do it with all your heart because that's the best you can do."