Trump's hair-raising moment

US President Donald Trump's hair has been a source of fascination and derision for years. Photo / AP

It's been the source of much curiosity and debate.

But a viral video seeks to demystify the president's hypnotising hairdo.

The footage shows Donald Trump as he hops up the steps to Air Force One at Joint Air Base Andrews before flying to Mar-a-Lago on February 2.

Trump was boarding Air Force One on Friday, February 2, 2018, at Andrews Air Force Base when a gust of wind revealed his bald spot. Photo / AP

As he bounded up the carpeted stairs, his wispy locks were whipped by the stern breeze.

One flap of hair flipped over on the side of his head to expose a seldom seen bald spot.

The video circulated yesterday and some excited users touted it as final proof that the president's unique look is the result of a heavy-handed combover.

The footage has been viewed more than 100,000 times on YouTube since it was uploaded.

Though some questioned whether the video itself is real, official press photographs from the same day appear to verify it.

It was confused with a separate appearance on February 5 when the president was joined by Melania to board a flight to Cincinnati.

On that day, the winds did their best to mess with his do but it stayed, for the most part, firmly in place.

Twitter users reacted in astonishment to the video of his bald spot.

It's sentient. His hair is literally waving goodbye.

— Soliloqueue (@Soliloqueue) February 7, 2018

Either grossly fascinating or fascinatingly gross. #TrumpHair https://t.co/LRVudzYMhs

— leefishman1 (@leefishman1) February 7, 2018

The answer, my friend, is blowin' in the wind... #TrumpHair #HairForceOne #AirForceOnce pic.twitter.com/ZZQoNzefe5

— Rick Horowitz (@Rick_Horowitz) February 4, 2018

The Emperor Has No Hair.

— watertigernyc says "WEAR A DAMN MASK!" (@watertigernyc) February 7, 2018

Trump's hair has long been a source of entertainment and mystery.

During his campaign, he sought to debunk the confusion by letting Jimmy Fallon mess it up during an appearance on his show.

To his naysayers' disappointment, his goldy grey strands remained rooted on his head.

Ivanka Trump allegedly spilled the beans about her father's hairstyle to close friends. Photo / AP

Ivanka Trump is said to have joked about it to her friends, revealing that her father's hair is the result of a 'scalp reduction surgery' and creative styling.

Michael Wolf, the author of the bombastic White House tell-all Fire and Fury, wrote: "She often described the mechanics behind it to friends: an absolutely clean pate - a contained island after scalp-reduction ­surgery - surrounded by a furry circle of hair around the sides and front, from which all ends are drawn up to meet in the center and then swept back and secured by a stiffening spray."