Conspiracy theorists think ‘giveaway’ detail just proved Melania Trump isn’t actually Melania Trump

Everyone's favourite conspiracy theory is back - the 'fake Melania' body double.

For those who are yet to encounter it, essentially, a group of conspiracy theorists are convinced that sometimes US President Donald Trump, 79, switches out his wife, First Lady Melania, 55, for a body double.

It keeps resurfacing time and time again, usually when the political pair do a joint public appearance and social media users analyse their every move.

While there's no evidence to back it up and Trump himself has previously dismissed it as 'fake news', believers cite things like large accessories and a difference in mannerisms as supposed evidence.

And now, people are back at it again after Trump and Melania touched down in Washington, D.C yesterday (30 November) following their Thanksgiving trip to Florida.

Footage shows them departing Marine One in the evening, with Trump heading down the aircraft stairs first and then being joined by Melania.

The US President and First Lady returned to Washington DC yesterday evening following a trip to Florida (Mandel NGAN / AFP via Getty Images)

They held hands and made their way over to the White House as reporters snapped pictures. However, it wasn't their mannerisms or body language this time that sparked the theory to reignite, but an unexpected detail in what Melania was wearing.

The First Lady was donning a dark green trench coat, brown heeled knee-high boots, and a large pair of sunglasses - with the latter causing confusion.

Social media users can't understand why Melania was wearing a pair of sunnies at night time, and took to Twitter to theorise.

One person penned: "She is a fake Melania, which is why she has to wear dark glasses when it’s pitch dark outside."

While a second agreed: "Her face is different. Different body language, tossing her hair, Melania isn't a hair tosser."

And others added: "Not Melania," and: "The Melania body double is wearing sunglasses at night."

"Fake Melania wearing sunglasses at night is a giveaway," commanded someone else.

Conspiracy theorists are convinced it was a 'fake Melania' who stepped off the aircraft (Bloomberg/Getty Images)

While others chimed in with: "Why is she wearing sunglasses?" and "She's not really Melania. She's one of the substitutes."

"I am looking and wondering is that the real Melania or maybe the fake Melania??? I keep going back an forth..." reasoned someone else.

Now, we know the First Lady is a fan of a pair of sunnies, and it's not the first time she's been spotted wearing them at night, not to mention all the cameras and flashes going off.

Someone else offered up a reason, quipping: "Looks to be a lot of flashing cameras and lights, they seem very bright."

The same thing happened in September when the pair returned late at night following their two-day state visit to the UK.

And in November last year, Melania faced similar accusations for wearing sunglasses indoors.