On the eve of our interview with Arsenal right-back Mr Héctor Bellerín, Channel 5 aired a documentary charting the famous feud between his manager Mr Arsène Wenger – who recently announced his departure from the club – and ex-Manchester United boss Sir Alex Ferguson. It serves as a reminder that, from the late 1990s to the mid 2000s, the pair oversaw some of the most explosive games in the Premier League. Things have changed since then, of course. Big money has blunted the rivalry, Arsenal are not the force they once were, and managers are not afforded anything like the two decades Mr Wenger, who signed Mr Bellerín as a 16-year-old tyro from Barcelona FC, has experienced at the helm. But even in the new, fickle, fast-paced game that has ushered his manager out, the Spanish defender, now 23, is, in many respects, something of a mould breaker.

He’s a vegan, for starters, which is unexpected in his line of work. He hasn’t eaten meat or dairy all season and, he says, he has never felt better. “When it comes to nutritional literature, everyone is very old-school,” he says as he sits on a couch in an east London studio, two days before the first of two semi-final Europa League matches with Atlético Madrid that will make or break Arsenal’s season (break, as it turns out – it will be Atlético facing Marseilles in next week’s final). “‘You need milk, eggs, meat.’ But actually, you are able to get the same amount of protein, carbohydrates and vitamins from plants.” He lauds its positive effect on the environment, and says his recovery time after games has vastly improved. “I used to be that guy who snoozed [through] the alarm 20 times. Then all of a sudden I was waking up with the sun at 7.00am.” And that’s not all. “I’ve also introduced yoga and meditation,” he says.

His attitude to social media is refreshing, too. Unlike some of his peers (the Twitter account @BoringMilner satires dull footballers particularly well), the wing-back is not afraid to speak his mind. “We live in a time where people get offended too easily,” he says. “If you care too much about offending people, you wouldn’t say anything.” He’s fun, too. Shortly after he broke into the Arsenal team, about four years ago, it wasn’t his lightning quick runs (he is one of the fastest players in the Premier League) that were going viral, it was his oddly authentic London accent – and he was more than happy to play along. “They call me the Spanish cockney,” he says. “It’s a compliment.” On Twitter, he can be seen ribbing opponents (and Mr Piers Morgan), chatting to Mr Jeremy Corbyn or tracking down a devoted fan to pay them a surprise visit. And he uses Instagram to document his love of clothes, something he calls his “second passion”.

Lots of footballers like fashion, of course. The money in the game – Mr Bellerín reportedly earns around £100,000 a week – means any professional can afford to wear what they like. But not all footballers are necessarily known for effortless style. “I like to call them brand whores,” says Mr Bellerín. “Let’s see who can have the biggest Gucci logo or have the most glitter on their shoes.” Mr Bellerín can dress, and he doesn’t take himself too seriously. Not that you really can if you’re wearing up-to-the-minute streetwear.

Mr Bellerín captured our attention when he wore Balenciaga Triple S sneakers, Fear Of God tartan trousers and a Fear Of God trucker jacket at London Fashion Week in January this year. “I love Jerry,” he says, referring to the Fear of God founder, Mr Jerry Lorenzo. “I love how he’s shaping the way young people dress.”

He was also seen wearing Zimmermann silk pyjamas and Gucci dragon-embroidered Princetown loafers. And it worked. Just about. “After that night, some of the players printed out pictures of me and put them in my locker,” he says, laughing. “At least that means they’re paying attention. There is no limit to what you can wear. That day I wanted to wear my pyjamas with a very cool Neil Barrett jacket. I was really comfy. I could come straight from my bed – I’d recommend it.”

In the same month as the London Fashion Week sighting, Highsnobiety ran a story naming him the best-dressed football player in the world. The football magazine Mundial, whose retro aesthetic reflects some of the football-influenced clothes currently in fashion (see Mr Gosha Rubchinskiy), sent out a Tweet collating some of his jazzier looks, joking that the Spaniard was an avid reader of niche style site Four Pins. If there were ever a footballer worthy of the label “hipster”, it is Mr Bellerín. And he’s clearly enjoying himself. “Streetwear reflects the time in my life that I’m at,” he says. “I’m young, I’m single again, I’m with my friends all the time and I’m expressing myself. People are recognising that I’m not dressing like every other footballer.”

His appreciation of clothes is not a new hobby. Fashion has always been in the family. “What a lot of people don’t know is that my mum and my grandmother have made clothes since for ever,” says Mr Bellerín. “My grandmother had her own factory back in Spain. When I wasn’t playing football, I was cleaning the threads from the floor. She taught me how to hem my trousers. I’ve got a sewing machine at home. I’ve got all the stuff. Some people don’t understand. They think I’m just putting up pictures to show how cool I am.”

There is a view among some diehard football fans that their heroes should stick to what they know – the game that they are paid handsomely to play – and some can be more than a little vocal about it. If you need an idea of fans’ enthusiasm, look at ArsenalFanTV, an oft-ridiculed, rather hysterical YouTube fan channel that Mr Bellerín seemed to criticise during his Oxford Union Q&A in February this year. He says that he often receives negative comments for what he says and does in his spare time. This would affect him at the start of his career, but he has since gained perspective. “For you to be going on someone’s profile to attack them – what is your life outside that computer?” he says. “It actually makes me laugh. Some people think that 24 hours a day you should be posting about football, football, football. That’s not sane at all.”

It is clear that Mr Bellerín is not afraid to enjoy life outside his main line of work. He has another job, for a start. After enrolling on a marketing diploma a year and a half ago, he has since set up a sports marketing agency with his best friend. “We have 16 players signed up to it and we take care of social media, commercial contracts – everything that’s off the pitch.” He also owns a restaurant in Madrid. He reads compulsively about tech, has an obsession with Mr Elon Musk (he often takes aimless drives in his Tesla car because he loves it so much), goes to reggaeton gigs, visits the Tate Modern on a Sunday, and does what he can for charities. To a cynic, this could be him cultivating a “nice guy” image for a polished personal brand, but he displays a genuine interest, and only does so when asked. “One of my best friends had a cardiac arrest playing football,” he says. “He survived and he started his own foundation, which I support. I tried to help with Grenfell, too. We’re doing stuff with WaterAid right now. There are always new things you can do.”

A more obvious reason Mr Bellerín has experienced some negative feedback – from fans and the press – is because things on the pitch haven’t gone exactly to plan. His form has not been as consistent as it was a few seasons ago, when he enjoyed the lack of expectation. “At the beginning, I was someone who was doing really well. Then when things started going not that well, everything was just negative, negative, negative,” he says of the reaction from some fans.

With this in mind, does he think he deserves to go to the World Cup in Russia with Spain this summer? The provisional squad list is due to be submitted by 14 May. “I don’t know,” he says, suddenly becoming a little more serious. “There’s a lot of competition. I’m not in a position to compare myself to other players. That’s for the new coach. My dream is to go to the World Cup. But there are other things in life – discovering the world, seeing my family. As a team, if you don’t have the best season, it doesn’t help. It’s been a tough one.” Arsenal are sixth in the Premier League. “We were doing well until November. We always have that period where we suffer a little bit. As a team, the most important thing is results. If you can win beautifully like [Manchester] City do – even better.”

Would he consider playing for another team, then? Juventus, Chelsea and Barcelona, his childhood club, are rumoured to be interested in him. “I don’t know what to say,” he says. “Football always changes. I’m so happy here. This has been my home for seven years. I sound like a Londoner, my friends are from London – it’s the place I want to be right now. In the future, you never know. Obviously, I grew up in Barcelona, and when I watch them play I want them to win. The team are always going to be in my heart.”