In some ways, this is nothing new. Pop culture has always had an appetite for seeing double: Mary-Kate and Ashley Olsen became wildly successful child actresses in the Nineties, and now run fashion label The Row; Dubliners Jedward are still remembered a decade after they appeared on The X Factor. It is big business on screen, and on social – not just for people, but things: Symmetry Breakfast (which, as you might imagine, posts identically laid out morning fare) has 771k followers on Instagram, and has since secured Michael Zee, the Londoner behind it, a book deal.
Twinfluencers are now in on the act and, able to analyse the popularity of their pages, tailor-make content for a hungry crowd. "When we dress exactly the same on our Instagram it is much more popular," explains Ayse Clark, 24, who runs a YouTube channel full-time with her sister Zeliha from their Norwich home.
The pair are strikingly similar, even for twins. They keep their dark brown hair long, and combed into a centre parting with no fringe. And then there are the clothes – one of their videos, in which they visit Primark, has been viewed 165k times. "We went shopping today and we just bought everything the same", says Ayse. "We do have the same sense of style". They appear to have similar taste in men as well – each has a boyfriend called Ben, both of whose middle name is James. The four of them live together, and recently all holidayed in Malta.
It may all sound like overload, but twins are a social media goldmine, where duos' natural chemistry makes for engaging viewing. "It's like having a wingman", explains Nico. "Engagement is higher when people collaborate, because you get two personalities."
This is certainly true for Niki and Sammy, who found that their videos as a pair were more popular than Niki's initial solo attempts. Their performance on screen is so seamless it looks scripted. "Having the same mind helps you as presenters because of the non-verbal communication", says Sammy – something in which they are well versed as, like many twins, they spoke in their own language as children.
Ironically, the sameness of twins helps them stand out in an increasingly saturated influencer market. "It's a niche, and people are running out of niches", says Nico. Niki and Sammy have sought to stand out by making a second channel centring around Korean pop music. "Everyone has their USP and ours is that we're twins that like K-pop", Niki says.
Having a twin around also helps influencers to stay sane in a job which could otherwise mean being alone in your bedroom all day, talking to strangers on the internet. "The mental health side of being a creator online is not touched on much", says Sammy. "Without someone else there it's easy to find yourself on a negative mindset when you're a slave to an algorithm that doesn't care about you."
Ayse and Zeliha agree. "It's nice not doing it on your own", says Ayse. "I have heard a lot of people who say the industry can get very lonely, so I'm glad that I can have my twin" – not least in fending off unpleasant comments from watchers, too.
The pair "love being twins" and claim to never get sick of each other, despite living and working together. And they are not just twinfluencers, but twin twinfluencers. They have 17-year-old identical twin sisters Ceylan and Ceyda, who sometimes make appearances in their videos. This double mirror image is difficult to take in visually, especially when you know the odds of a family like this is 1 in 52,000.
A double dose of twins has also proved popular for Victoria Morrell's Instagram page @mama_and_the_peas, where she posts about her five sons, which include two sets of identical twins. The pairs, aged 6 and 1, are usually dressed similarly, if not completely the same, with her two-year-old slotting in between.
"I think I'm more popular because I've had the two sets of twins", says Morrell, 35, who is on a break from her career as a solicitor. She says she started the page to show that it is possible to look after five children and that twin pregnancy isn't always like the horror stories you find online. "My inbox goes crazy every evening with people asking for advice," she explains.
"It's so hard to get out of the house when you have twins", says Morrell, who looks after the children while her accountant husband is at work. "If you go to a baby group you're like a circus show. You're often known just as 'the one with the twins'. Then if you are doing well, some people step away because you're coping with twins and they're not coping with one."
Companies are more enuthsiastic: keen to get in on the audience of followers she has built, clothing, buggy and crockery brands send Morrell products to try out, while out and about, "people come up and take pictures, she says. On a trip to London this week, "tourists would come over to you and go crazy."
And beyond those interested in the optics alone, scientists want to know more about how Morell has produced such a phenomenon – so much so that she and her husband were asked to donate eggs and sperm in order to guide further research.
"I am fascinated," she concedes of her multiple-twin setup. "I still can't believe it'."