We learned recently that classic Doctor Who monsters the Ice Warriors - last seen on screens in 1974 - are to make their TV comeback when series seven returns later this year.
But it turns out showrunner Steven Moffat was initally very dubious about resurrecting the warlike Martians, worrying that they were exactly the sort of creatures people thought of as “rubbish Doctor Who monsters.”
"It was Mark Gatiss's idea and it was very much his pitch - he'd been pitching for Ice Warriors for a while. I wasn't tremendously persuaded,” said Moffat.
“I'll be honest: I thought they were maybe the default condition for what people thought of as rubbish Doctor Who monsters - things that moved very, very slowly and spoke in a way that meant you couldn't hear a word they said.”
So how did Gatiss convince Moffat to give the Ice Warriors a another chance?
"Mark came up with a couple of very clever ideas, which he pitched to me over the phone in what was meant to be a Sherlock conversation," Moffat told Gallifrey One. "He had a couple of really stormingly good ideas, and it's a great episode, an absolute cracker of an episode."
Moffat also addressed a possible return for another classic villain, the Doctor's fellow Time Lord the Master, saying he was again wary of bringing him back but that "a great story" could convince him.
“I think there's a danger with giving the Doctor an arch-enemy like that - it's sort of limiting and a little bit cartoony, I suppose,” he said.
“But I thought what [former Doctor Who showrunner] Russell [T Davies] did with it - which is making him a complete lunatic - was really, really brilliant and really clever. I did think he sort of ended that story and ended it rather brilliantly. But what it comes down to is: do you have a great story or not? Do you have a great idea or not? So [reviving the Master] is certainly not off the table, no."
Doctor Who will return to BBC1 on Saturday 30 March.
Watch the whole of Moffat’s Gallifrey One interview below: