Kelsey Anne Gregg, who splits her time between the Bear Flag state and the Czech Republic, shared the clip on Wednesday after enjoying the outdoor celebration. The video has gone viral and already been viewed more than 2.5 million times.

Gregg, who describes herself as a Mexican-American, said: “I went to an American themed party in Europe (as an American.) I was not disappointed. Those costumes. Everyone in America looks like this 100%.”

She captioned the clip “when Europeans dress up like Americans,” and the footage shows a number of men all wearing red plaid shirts.

The men, who all turned up in effectively the same outfit, even lined up for a photo, showing off slight variations in the patterns.

Most paired the top with jeans or denim shorts, while there’s an interesting selection of headgear, ranging from baseball caps to straw hats.

And there’s one man who simply turned up to the party, believed to have been held in Prague, draped in an American fag.

The video has amassed numerous comments, as debate raged as to whether the costumes were Canadian or American, while one person thought they were Amish.

Lo Christianson simply said: “The guy wearing a USA flag.”

Also praising him, Christine D wrote: “The flag guy was the only one who understood the assignment.”

Violet thought: “Flannel is Canadian. American is tank tops and cargo shorts I don’t make the rules.”

Sara agreed, saying: “I came to say this was Canadian and the comments did not disappoint.”

Kendra defended the flannel choice, writing: “People trying to say flannel isn’t American. Yes it is. The straw hats aren’t a look though. Baseball hats was the right choice. The flag cape is [thumbs up].”

Ben Hughes asked: “What would America dress up as if they were trying to be British? A top hat?”

Charlotte pointed out: “What cracks me up is that it isn’t the same shirt, they just buy this because it was available at the local H&M, they really all had the same idea.”

Bella reckoned: “Americans wear camouflage and cargo shorts or muscle shirts.”

Carrie was bemused, as she commented: “Do they do this? Do they do this for real in Europe?! I love it. I’m obsessed.”

“They think we’re Amish,” said one TikToker.

Nadia Quinn raved: “Honestly, pretty good job.”

Fadi joked: “Was their only reference the “Cotton Eye Joe” music video?”

Clearly a fan, I am said: “Why is this so oddly wholesome and funny?”

While Jessika added: “As a midwestern American, I crown the trucker hat guy the winner. If I were to see him at the store, he would blend right in.”

Newsweek reached out to Gregg for a comment.