The star of the BBC's new lavish wartime drama, SS-GB, says he's "more anxious about this than anything I have ever worked on" because the series is filling the prestigious BBC One 9pm Sunday night slot - an hour that's become synonymous with so-called "event television".
"We didn't know that we would occupy that slot when we were making it," Sam Riley says.
"I am anxious and excited. My father said to me, 'people might actually watch this one' - as I'm rarely recognised in the street because of my work."
SS-GB, which has been adapted for television from the 1978 Len Deighton novel by the writers of Skyfall, imagines what would have happened to Britain had the Nazis successfully invaded in 1940.
There have been some complaints from members of the public about the sound quality, after the first episode aired on Sunday.
Riley, who has starred in films such as Maleficent, On the Road and Control, a biopic of the band Joy Division, plays Douglas Archer, an officer working simultaneously with the Nazis and the British Resistance.Image caption How would Britons have reacted if their country had been occupied?
During the last year, the 9pm space has been occupied by Golden Globe winner The Night Manager, starring Tom Hiddleston, as well as Sherlock, and most recently, sexual thriller Apple Tree Yard, generating ratings of up to eight million, as well as online "Twitterstorms" over plotlines from the viewing public.
"I think we had a very different budget from The Night Manager," Riley points out.
"And although it's been done by the fabulous Bond writers, it's not a 'crash boom bang wallop' sort of series, it's more in the vein of Tinker Tailor Soldier Spy. It's different - but as for the pressure to succeed, we can't do anything about it now."
Riley adds that though the series was filmed in 2015, "inevitably everyone's drawing parallels with the rise of right-wing populism across Europe, and we can't really ignore that. In a sense, the questions being asked of my character - to speak out or to keep his head down - we might all well be asking in the future. And yes, everyone's asking me about Trump."
SS-GB is directed by a German filmmaker, Philipp Kadelbach, and has a large German cast, excluding, according to Riley, "any well-known British actors with a bad German accent."
The actor lives in Berlin with his family and speaks German fluently, and explains that he "did an unusual thing for me when I heard about the series. I got Phillip's number and called him and said, 'if you haven't already cast this role, I'd really like to meet with you to talk about playing it.'"
Re-imagining the outcome of the Second World War has been a popular theme with writers other than Deighton -from CJ Sansom's Dominion, to Philip K Dick's The Man in the High Castle, which has also been adapted for the screen by Amazon.
"I don't watch much TV and I only heard about the American show when I was preparing for this one," Riley explains. "They're very different to each other. Theirs is post-war and has sci-fi elements, Len based his novel on the actual Nazi plans of how they would take us over. It's an alternative history, but it's grounded in the 'what if' scenario."
Although many scenes were shot in London, Riley says that set designs featuring swastikas were only used indoors, "because we were cautious not to offend or upset Londoners or nationalities that may have been occupied by the Nazis. If we were outside, in between takes the soldiers would wear ponchos.
"The Nazis used powerful imagery, and their symbol is unforgettable. During the scenes, partly I'd be thinking what an incredible job the set dressers had done, but there were shocking moments -a scene in Highgate cemetery with Nazi soldiers chilled me inside. And I got upset when I saw a yellow star on a costume. These are the moments when you are sobered."
The series has been sold worldwide, including in Germany, with plans to continue should it be a success. But how will the British react, when, as Riley says, "so much of our psyche is about the perception of victory in World War Two - which needs to take into account of what America and Russia also did.
"Our war movies and heroics are a fixture on Christmas television, and I adored them like every other school boy. But we live with a slightly false pride in Britain because we were never occupied. Had we been we would have had a lot more questions over who had collaborated. We all like to imagine we'd have resisted, but when it came down to it, knowing the price of it, how many of us would have had the strength of mind to do it?
"If you walk around Berlin, the Germans, out of all the countries in Europe, certainly don't want to forget their past and it's very important that you see the past everywhere you go.
"I imagine Germany would be the last country in Europe to return to right-wing politics, and we should be looking at our own back yard."
SS-GB airs at 9pm on BBC1 on Sundays