Donald Trump appeared to debut a slick new hairstyle ahead of his visit to meet the Queen in London this week, but there is speculation his new look may have just been a case of "hat hair".

The US President's bouffant hairdo is frequently the subject of jokes and many were surprised when he appeared with a slicked back style on Sunday.

In a style reminiscent of 1980s icon, the Wall Street character Gordon Gekko, Trump's look moved away from his typical, more orange, style.

Trump arrives on stage to receive a prayer at McLean Bible Church. Photo / AP

The colour looked to be a softer, more natural blonde shade and the hair was also slicked back.

It seems the latest hairstyle may simply have been a case of hat hair.

Trump was photographed during an unannounced visit to an evangelical church in Virginia to pray for 12 people who were victims of a shooting on Friday.

His visit took place after a golf outing and he was still dressed in his golf shoes and shirt. He looked visibly uncomfortable when he had to remove a baseball cap he was wearing.

President Donald Trump shakes hands with Pastor David Platt after Platt prayed for him at McLean Bible Church, in Vienna, Va.. Photo / AP

The President's slicked back style had Twitter users wondering what was going on.

Others approved of the new look and thought he should make it permanent.

Wow he looks like a real person and not an orange cheeto with fly away hair https://t.co/5QL71xfizQ

— Wonder Woman (@NickoleRenee) June 2, 2019

natural hair Trump looks like old Biff from Back to the Future 2 and that ruined my whole week and it's only Sunday pic.twitter.com/IsSiWkRV4c

— bᵣycₑ🌹😔🤙🏻 (@bryceshreve) June 3, 2019

Trump takes off his cap and reveals his non comb over hair for the first time. And of course it actually looks better. pic.twitter.com/HyL9h2DarH

— Mike Sington (@MikeSington) June 2, 2019