1) Felix Arvid Ulf Kjellberg and Marzia Bisognin
Combined subscribers: 39 million
Specialist subjects: Video games (Felix) and style (Marzia)
Was it love at first byte? Mazia: 'I first saw Felix on one of his 'scary' videos and instantly started laughing at his high-pitched screams!'
Best on-screen moment? Felix: 'Doing a sumo video together!'
Next up? 'Life together in our cosy Brighton flat with our pugs Maya and Edgar.'
2) Zoella Sugg and Alfie Deyes
Combined subscribers: 10 million
Specialist subjects: Fashion, beauty, lifestyle (Zoella) random stuff (Alfie)
Mush-factor: These two prefer to keep their online profiles relatively separate, though will pop up in the background of each other's vlogs now they're living together. 'For those of you who are gutted that Alfie is not a single man' wrote Zoella on her blog when the relationship was revealed, 'I give you 100% permission to stalk, flirt and hug him until he is blue in the face!'
Anything else? Twitter went into meltdown recently when the pair moved into a £1 million pad in Brighton together.
Read More: Zoella Net Worth: These Figures Will Blow Your Mind
3) Tanya Burr and Jim Chapman
Combined subscribers: 4.8 million
Specialist subjects: Beauty (Tanya) and pop culture and men's fashion (Jim)
Mush factor: 3/5
Pet names? Jim: 'Loads! T-bomb, Teebs, Kiddo. We've been together for over eight years, so hundreds of pet names have come and gone.'
Next up? Tanya: 'Touring for my book Love, Tanya, and getting married!'
4) Niomi Smart and Marcus Butler
Combined subscribers: 4.5 million
Specialist subjects: Random stuff
Mush factor: 5/5
When did you meet? Niomi: 'We went to school together so we were friends then. I was always attracted to Marcus' cheeky smile!'
Nicknames? Marcus: 'Nimbob came first'
Next up? Marcus: 'Moving to either London or LA.'