The author was responding to a post by Twitter user Andy Dobson, who regularly posts photos of his son Rory dressed up as the fearsome villain featured in the BBC show.
In it, Dobson shared a photo written by an unnamed person who called Rory’s costume “crap” because he was holding the Dalek’s weapon (in the makeshift costume’s case, a whisk) in the incorrect hand.
“Stop posting photos of that kid in his crap Dalek costume – he’s not even holding the energy weapon in the right hand,” the message read, adding that he was “embarrassing proper Doctor Who fans”.
The message continued: “Get off Twitter and leave fandom to the true fans who care about the show.”
Dobson shared the message alongside the adorable photo of his then 18 month-year-old son, writing: “Well, this is a charming DM from a ‘true fan’, received this morning.”
He quipped: “I do get the distress caused by the whisk being in the wrong hand – but my son was only 18mths old and is much wiser now.”
American Gods and Good Omens author Gaiman shared the post to his followers, writing: “True Doctor Who Fans know you can hold the whisk in either hand. As long as you remember to say ‘Exterminate’ or something vaguely like it, you are a real Dalek.”
In response, Dobson thanked Gaiman.