Trump briefly swapped his trademark hairdo for a slicked-back style that makes him look totally different

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A composite photo showing President Donald Trump in the UK on June 3 2019 (left) with his regular hair style, and (right) sporting a different look the previous day at McLean Bible Church in Vienna, Virginia.

• President Trump showed off an unfamiliar, slicked-back hairstyle on a visit to a Virginia church on Sunday.
• On social media people speculated whether the president was sporting a new style ahead of his state visit to the UK, or just suffering from "hat hair."
• The president once again had his trademark swept-back style when he stepped off Air Force One in the UK on Monday morning. 
• Trump's hair has long been the source of speculation, and in his 2018 book "Fire and Fury," Michael Wolff claimed Ivanka Trump has revealed its secrets to friends. 
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President Donald Trump showed off an unfamiliar look on Sunday -  swapping his trademark swept-back style for a slicked-back look which caught many by surprise. 

The president had the new style at a visit to a Virginia church on Sunday before flying to the UK for a state visit. By the time he landed just outside London on Monday he had returned to his familiar style. 

On social media, the president's short-lived new style generated intense debate, with some speculating that the president's uncharacteristically flat look was actually "hat hair."

Trump arrived at the church, for a service for victims of a mass shooting in Virginia Beach, straight from the golf course at his club in nearby Sterling wearing a baseball cap and slacks. 

At the McLean Bible Church, Trump removed his cap to join pastor David Platt in prayer for the 12 people killed in Saturday's mass shooting, and did not address the congregation. 

Trump's hair has been the source of speculation and fascination over the years.

Jimmy Fallon confirmed it was real during the 2016 campaign, when Trump made an appearance on Fallon's show in 2016 and allowed the host to mess up his hair. 

According to Michael Wolff's 2018 White House book "Fire and Fury," Trump's daughter Ivanka has revealed to friends the secrets of here father's hairstyle, saying that it is the result of surgery and an elaborate process of sculpting and hair spray to fix it in place.