Donald Trump is standing out from the crowd at the G20 gathering in Hamburg - and not just because of his politics.

Photos from the international meeting show Trump is the only one of the world's leaders not to wear a special G20 pin, instead choosing to don an American flag.

That's sent his supporters into a frenzy of approval online - but Barack Obama got there first, donning an American lapel pin at last year's G20.

Scroll down for video

Standing out: Donald Trump was seen wearing an American flag pin to the G20 summit in Hamburg, Germany - unlike the other attendees, who wore the G20 badge

Blast from the past: Trump's fans were enthusiastic about what they saw as Trump rejecting globalism - but Barack Obama wore a US flag pin to the G20 summit in 2016 (pictured)

Trump's apparent challenge to the G20 status quo is a small one, but to his followers a deeply symbolic one.

His whole election campaign was based around rejecting the ties to other countries that had been developed by successive Republican and Democrat administrations.

They included promising to throw out international trade deals that he said were bad for America - such as the Trans-Pacific Partnership - and levying heavy taxes on goods manufactured in Mexico.

He has also gone his own way with climate change, withdrawing from the Paris climate agreement to the disquiet of many other international leaders.

To that end, it would make sense for him to wear the American flag on his chest, and not the G20 logo.

Particularly as that logo is of a reef knot that - according to the G20 website - represents 'interconnectedness'.

Certainly the pin caught on with his supporters online, who called it a rejection of 'globalism' represented by the other countries.

Flagged up: The US flag pin stands out from the G20 one (left), which has the G20 logo of a reef knot symbolizing interconnectedness, along with the Elbphilharmonie concert hall (right)

Twitter user lb fowler jr md wrote: 'Trump refuses to wear G20 pin - opts for American flag which trumps lol any globalism symbol!'

ActuallyArlie wrote: 'I'm absolutely devoted to Trump and his mission... which is our mission. A simple thing like the flag pin speaks volumes.'

And Mary Baker enthused 'GREAT AGAIN,' adding 'WAY TO GO MR PRESIDENT.'

Meanwhile, Nancy Kennedy-Coon got in a cheeky jab at the leader by posting a picture of a combined US-Russian flag pin, saying it might 'solve Trump's lapel pin delimna [sic].'

Praise: Trump got kudos online for his sartorial choice, which many of his supports saw as him rejecting 'globalism'

Devotion: This user said she was devoted to Trump 'and his mission.... which is our mission.' Trump has gone his own way, even drawing out of the Paris climate agreement last month

Dilemma: This user cheekily offered up a pin with a combined US and Russian flag, asking if it might solve the president's dilemma

However, Trump is not the first to eschew the standard-issue G20 pin for an American flag one.

Photos from last year's G20 gathering show then-President Barack Obama sporting an identical flag badge on his lapel.

Obama was photographed at the event - including at the photo op for the world leaders at the start of the summit - sporting the unique pin.

As well as the reef knot, the G20 pin for this year also has the shape of the Elbphilharmonie concert hall, which was attended by the world leaders at a special concert before the meetings on Friday.

That same day the world leaders lined up for a photograph to commemorate the occasion.

Trump was a man apart there, too - placed on the far end of the front row, almost the last man there aside from Emmanuel Macron.

Meanwhile Angela Merkel stood near the center, flanked by President Xi Jinping of China and President Mauricio Macri of Argentina.

That's because the leaders are placed in order of who has been in office longest - with the exception of the host country's leader, in this case Merkel, who goes in the center.