​The British Open kicks off on Thursday, offering fans around the world a chance to see the biggest and best names taking part in the oldest major tournament professional golf has to offer.


Despite making their name on the green, some of the sport's most well-known stars actually found their first love on a football pitch.


Here are 10 of the biggest names you can hope to see throughout the British Open and where their not secret allegiances lie in the world of football.


Jon Rahm

Jon Rahm

Coming from Spain's Basque Country, it will come as no surprise that Jon Rahm quickly became a supporter of Athletic Club - more commonly known as Athletic Bilbao.


It wasn't just from the stands where Rahm showed his passion for football, however, as the 24-year-old used to be a keen player as a youngster.


"In fútbol, I wanted to be a goalkeeper," Rahm told Yahoo Sport. "I'll never forget when I was 13, we played in a big tournament with other top teams. We were leading 32 in the final seconds, and there was a penalty kick, so I had to stop the shot. 


"Both teams were lined up watching, all the fans were yelling, and I stopped the ball and we won. I loved that feeling, of everyone counting on me. But it can be hard to get that in team sports. In golf, there is that internal pressure on every shot. I think that's why I fell in love with the game."


Thorbjørn Olesen

The 2016 Turkish Airlines Open and 2018 Italian Open winner breaks the mould from what most fans deem to be acceptable in the world of football, as Denmark's Thorbjørn Olesen supports two different teams.


Sitting just a few clicks away from his hometown Furesø Kommune, Olesen follows Denmark's most successful team FC Copenhagen.


But the 29-year-old also has allegiances in the Premier League, and Olesen is among a handful of players to also have Manchester United as their team.


Tyrrell Hatton

Just in case you couldn't tell from Tyrrell Hatton's personalised wedge, the 27-year-old has placed his allegiances in the red half of Merseyside.


He might come from north-west London, but Hatton's passion for all things Liverpool has already seen him build up a relationship with the Reds very own Yorkshire Figo.


"I’ve got to know James Milner - he’s played for Liverpool for the last few years and he’s a really keen golfer, so obviously when our schedules permit we try and get a game in," Hatton said, quoted by The Mirror.


"So for me, it’s quite cool to know a player from the team I support!"


Tommy Fleetwood

Tommy Fleetwood

Born just a few miles north of the city centre in Merseyside's biggest seaside town, it's perhaps no surprise to learn that Southport's Tommy Fleetwood is an Everton fan.


The 28-year-old was even invited down to Goodison Park two years ago to help promote the British Open in 2017.


Henrik Stenson

Veteran Henrik Stenson doesn't hide the fact that he's not the biggest football fan, but he's still got a team nonetheless.


Placing his allegiances purely down to where Jesper Blomqvist was playing at the time, the Nordic countries' first-ever champions is a low-key Manchester United fan.


Ian Poulter

Ian Poulter of England golf shoes

While some golfers might shy away from showing their allegiances too much, Ian Poulter - who's been as high as fifth in the world rankings during his career - doesn't hide the fact he's a massive Arsenal fan.


So much so that Poulter risked breaching rules when he wore an Arsenal shirt during one of his rounds at the Abu Dhabi Championship in 2006.


Poulter's ditched wearing his Arsenal jersey whilst on the green these days, but that hasn't stopped a decal or two appearing on his shoes during competitions.


Justin Rose

It's one thing being a fan of a team, and even being invited for a ceremonial appearance at a club's home stadium, but number four ranked Justin Rose once got a personal invited to Chelsea's training ground by then captain John Terry.


The 38-year-old even took part in a golf chipping competition at Cobham with some of the Chelsea team.


Francesco Molinari

Francesco Molinari,Alessandro Del Piero

Italian Francesco Molinari's first team was Inter, but the 36-year-old was also made to adopt a Premier League side once he moved to England in 2009.


Manchester United? 


Nope.


Liverpool?


Not a chance.


The 2018 Open Champion actually supports... West Ham!


"At the time," he said, quoted by ESPN. "Gianfranco Zola was the manager of West Ham and my coach, Denis Pugh, supports them - as do a few other friends of mine in London.


"He’s moved on since, but I’ve stuck with the Hammers."


Sergio García

31-time professional champion Sergio García might just be the most recognisable football-loving golfer, and for good reason too.


He was given the honour of taking an honorary kick-off for his beloved Real Madrid before a highly-anticipated El Clásico, but the 39-year-old is more than just a football fan, as he's even dipped his toes in the water behind the scenes.


García is also the chairman of his hometown side Club de Fútbol Borriol, based in Castellón in the Valencian Community, in Spain's Tercera División. 


Rory McIlroy

Rory McIlroy

A boyhood Manchester United supporter, former world number one Rory McIlroy was offered the chance to present the Claret Jug at Old Trafford after winning the Open in 2014.


But the 30-year-old has also done something which many United fans would consider a cardinal sin - backing Liverpool to win the Champions League final.


Before their final against Real Madrid in 2018, via the Liverpool Echo, McIlroy said: "As much as I’m a United fan, and United fans are supposed to hate Liverpool, I think it would be great to see a British team win, so hopefully [they will]."