Billy Horschel golf bag at Open Championship: Why American has West Ham colors, logo on bag at 2024 British Open

Billy Horschel went into Sunday's final round at the 2024 Open Championship with a one-shot lead over the rest of the field.

The 37-year-old coped superbly with the difficult weather conditions on Saturday and was the outright leader after Daniel Brown's double bogey on the 18th in Round 3.

Horschel has attracted plenty of admirers at Royal Troon this week, both for his exceptional play and his rather prominent choice of equipment.

His bag, which sports the colors and club crest of English Premier League side West Ham United, has provoked plenty of discussion among watching fans on social media — particularly those of rival teams.

So, how did a PGA Tour pro from Brevard County, Florida end up supporting a soccer team from the East End of London?

LIVE: Follow the latest updates from Royal Troon on the final day of the 2024 British Open

Why does Billy Horschel have a West Ham golf bag?

Horschel spoke before the 2024 Open Championship got underway about how he likes to bring out the West Ham colours when he's playing in the U.K.

The Florida native is a huge Hammers fan. He even spoke to the media this week about the Premier League club's transfer plans, suggesting it would be a mistake for them to try to sign N'Golo Kante.

"Whenever I try to come over here I try to get the West Ham bag out. Up the Hammers and come on you Irons," he said.

"Other supporters of other clubs have been gracious enough to be nice to me compared to how they may be to a fellow English person supporting West Ham."

Horschel's bag at the Open in 2024 is adorned with the West Ham crest and sports the famous claret-and-blue colours of the London club.

Why is Billy Horschel a West Ham fan?

It might seem a little odd for an American golfer to support an English Premier League team who have never won the top-division title and have spent most of Horschel's life in the shadow of fellow London clubs Arsenal, Chelsea, and Tottenham.

Well, Horschel owes his Hammers allegiance to the movie Green Street. The 2005 crime drama about football hooliganism, which stars Elijah Wood and Charlie Hunnam, was released while Horschel was in college. It's fair to say it stuck with him.

"During my sophomore year of college, I moved into a new apartment and the cable wasn't going to be hooked up for a couple of days so we went to Best Buy and bought a couple of DVDs. One of those DVDs was Green Street," he told Sky Sports before the 2021 Open Championship.

"I loved the movie, I loved Charlie Hunnam as an actor and obviously the film is about the firms [hooligan groups] at Millwall and West Ham. From there, I started following them. Since about 10-12 year ago I've been paying really close attention to them since NBC Sports starting showing Premier League games.

"I'm always watching their matches and any Premier Leagues actually, but I follow them [West Ham] very closely and I'm aware of how they're doing, the transfer window and just a die-hard supporter like I am for my Florida Gators."