Ben Whishaw, who plays James Bond boffin Q in the 007 films, is to star in a new espionage drama set in the capital.
The actor has been cast in the new BBC Two drama London Spy written by best-selling novelist Tom Rob Smith.
He plays Danny, described as a "hedonistic romantic", who is drawn into the murky world of the security services when his boyfriend disappears.
Rob Smith said: " Ben Whishaw is quite simply one of the best actors in the country. It's an extraordinary privilege, as a writer, to have him play the lead."
Filming for the five-part series starts next month.
Polly Hill, BBC head of independent drama, said: "This is a beautifully written love story, caught up in a spy thriller - a wonderfully complex and surprising story, of one man's search for the truth. It promises to be a treat for the BBC Two audience, continuing the channel's commitment to original authored drama."