- Photography by Mr Billy Kidd
Fraternal relationships - and 80 per cent of us have at least one - are often the longest of our lives. They outlast marriages, survive the death of parents, rekindle after quarrels that would kill any friendship. Blood is thick. Family ties cannot be undone by a decree nisi. These are the people with whom - through accident of birth - we share experiences, DNA and in-jokes that no-one else could ever get.
It takes two people to be one brother. We spoke to five pairs - interior designers, chefs, fashion designers, skateboarders, models - to ask them what it was like to grow up with each other and how that has shaped them as adults.
Some of their stories are serious, some are frivolous, but each one reveals a fraternal bond that is eternal.
Whose father was killed by a drunk driver? Which pair had a brawl that needed police intervention? And who was chosen ahead of his brother to spend a day completely naked with Ms Kate Moss?
Click through the thumbnails, above, to find out.
Styling by Mr Dan May, Style Director, MR PORTER
Interviews by Mr Dan Rookwood, US Editor, MR PORTER