Donald Trump has been caught looking at the solar eclipse without safety glasses, despite all expert advice saying this practice is dangerous.

“Looking directly at the sun is unsafe except during the brief total phase of a solar eclipse (“totality”), when the moon entirely blocks the sun’s bright face, which will happen only within the narrow path of totality,” Nasa wrote on a webpage discussing how to view the 2017 solar eclipse safely.

“The only safe way to look directly at the uneclipsed or partially eclipsed sun is through special-purpose solar filters, such as ‘eclipse glasses’ or hand-held solar viewers.”

But this didn't stop the President, who has a reported tendency to act against the advice of his aides, from sneaking a peek after taking off his protective glasses. He squinted as he briefly looked up at the sun.

Mr Trump watched the rare spectacle from the Blue Room Balcony at the White House – hundreds of miles away from the eclipse’s path of totality – next to his wife Melania and son Barron.

According to the White House pool report, the President initially gesticulated to a crowd of administration staffers gathered below the balcony and pointed to the sky. As he did so, one of the White House aides standing beneath balcony shouted “don't look!”

Solar eclipse 2017 Show all 12 1 /12 Solar eclipse 2017 Solar eclipse 2017 A handout photo made available by NASA shows the Moon as it starts passing in front of the Sun during a solar eclipse from Ross Lake, Northern Cascades National Park, Washington, USA, 21 August 2017. The 21 August 2017 total solar eclipse will last a maximum of 2 minutes 43 seconds and the thin path of totality will pass through portions of 14 US states, according to the National Aeronautics and Space Administration (NASA) EPA Solar eclipse 2017 The sun is projected on the ground glass (bottom) as photographer C.D. Olsen adjusts his replica of the Kew Photo Heliograph camera, which he will use to make a glass plate photograph of the total solar eclipse, outside the football stadium at Southern Illinois University in Carbondale, Illinois, U.S REUTERS Solar eclipse 2017 The sun emerges through clouds and fog cover before the solar eclipse in Depoe Bay, Oregon REUTERS Solar eclipse 2017 A boy uses solar viewing glasses as the sun emerges through fog cover before the solar eclipse in Depoe Bay, Oregon REUTERS Solar eclipse 2017 First responders and city officials man the emergency operations center in Charleston, South Carolina, on the day of the total solar eclipse AFP/Getty Images Solar eclipse 2017 A man looks through his solar viewing glasses after purchasing them to watch the total solar eclipse in New York City REUTERS Solar eclipse 2017 People are seen lining up outside the Smithsonian's Air and Space Museum as a sign indicates there are no more eclipse glasses on the National Mall before an eclipse August 21, 2017 in Washington, DC. The Sun started to vanish behind the Moon as the partial phase of the so-called Great American Eclipse began Monday, with millions of eager sky-gazers soon to witness "totality" across the nation for the first time in nearly a century AFP/Getty Images Solar eclipse 2017 Solar Eclipse in Depoe Bay, Oregon, U. REUTERS Solar eclipse 2017 People watch the start of the solar eclipse and raise their hands in prayer in an eclipse viewing event led by Native American elders, at Big Summit Prairie ranch in Oregon's Ochoco National Forest near the city of Mitchell on August 21, 2017. The Sun started to vanish behind the Moon as the partial phase of the so-called Great American Eclipse began Monday, with millions of eager sky-gazers soon to witness "totality" across the nation for the first time in nearly a century AFP/Getty Images Solar eclipse 2017 People line up on a bridge as the sun emerges through fog cover before the solar eclipse in Depoe Bay, Oregon, U.S REUTERS Solar eclipse 2017 The Sun rises behind Jack Mountain ahead of the solar eclipse in Ross Lake, Northern Cascades National Park, Washington, U.S REUTERS Solar eclipse 2017 The sun rises over Grand Teton National Park on August 21, 2017 outside Jackson, Wyoming. Thousands of people have flocked to the Jackson and Teton National Park area for the 2017 solar eclipse which will be one of the areas that will experience a 100% eclipse Getty Images

Mr Trump’s apparent failure to heed advice against looking at the sun was immediately mocked on Twitter.

“Thought warnings about Sun were fake news…,” wrote Twitter user Devin Duke.