When it came to actual filming, though, one of the biggest challenges for Riley was the early sequence in which he, with a sword, goes up against Capaldi's mighty spoon.
"The fight with a spoon was actually incredibly difficult," he says. "Because it's tiny. It's a spoon! So my aim had to be bang on, and Peter's blocking had to be bang on. It's not like a sword where you've got a foot length to clash into – you have to be so precise, but make it look like you're struggling. We spent ages on that rehearsal."
After the fantastic Doctor Who 'Robot of Sherwood' episode finished this evening, the BBC website uploaded a brilliant behind the scenes video, shared some great set photos from Caerphilly Castle, and posted a fact file for the episode. Lots of Tom as Robin Hood to be seen in these behind these scenes photos from Caerphilly Castle, too.
A quick-fire interview with Tom for Doctor Who TV, about Robot of Sherwood, has been posted online. Read it in full on the site. Tom's episode of Doctow Who will be on BBC One tonight at 7.30 pm.
Who do you play in this week’s episode and can you briefly describe your character?
I play a man who at least claims to be Robin, Earl of Locksley - someone that the Doctor is convinced never existed and is entirely fictional. He’s a man filled with passion and heart, and who finds pretty much anything and everything funny. Not least the Doctor himself.
What were you doing when you found out you’d been cast in Doctor Who?
Coincidentally, I was actually watching [episode writer] Mark Gatiss on stage in Coriolanus at the Donmar Warehouse in London. An offer came through whilst I was in the audience asking if I fancied playing someone rather iconic in Doctor Who. But then I had to hang up as I was disturbing the actors. (I'm joking. I picked up the email as I was leaving). The minute I read the script I knew immediately that I had to be a part of it.
What’s your first memory of Doctor Who?
EW has shared another new interview with Tom and Mark Gatiss. As well as chatting about tomorrow night's episode of Doctor Who 'Robot of Sherwood', Tom gives some new insight into season 3 of Da Vinci's Demons and Kill Your Friends, while Mark Gatiss explains how he and Tom met on the set of Poirot.
So how come Da Vinci’s Demons star Tom Riley is playing the British legend in the show? In truth, we didn’t bother asking the actor that spoiler-ific question when EW jumped on the phone with him and episode-writer Mark Gatiss earlier this week.
TOM RILEY: As Mark says, it’s interesting that when they show up, they’re straight in the middle of an Errol Flynn movie. On the page, [the character] had that feel of that traditional, heroic element. He’s almost too good to be true.
And are you too good to be true?
RILEY: Am I too good to be true? I’ll leave that to Mark. Mark?