Donald Trump will attempt to end speculation about his mental and physical suitability for the presidency by undergoing a formal health check.
The US President is to be examined by the same doctor as his predecessor Barack Obama and a summary of the results will be made public.
The physical test will last around two hours and include blood and urine tests, heart checks and even questions about his sleeping habits and sex life, according to medical experts.
It will be carried out at Walter Reed National Military Medical Centre on the edge of Washington DC, the country's largest military hospital, on Saturday NZT.
By undergoing his first formal medical check since entering the White House, Trump hopes to put to bed allegations about his mental state.
A controversial new book by journalist Michael Wolff claimed Trump was failing to recognise old friends and often repeated stories "word-for-word". The White House called questions about his mental suitability for office "disgraceful".
Meanwhile, Axios reported yesterday that Trump has shortened his daily schedule. He often begins his official work day at about 11am.
The news website, citing copies of the President's private schedule, said Trump's starts are much later than when he started the job. Axios says Trump has been demanding more "Executive Time" for his days. Officials said that "almost always means TV and Twitter time alone in the residence," Axios reported.
"Executive Time" is on Trump's schedule every day from 8am to 11am.
Axios reported that President George W. Bush usually began his time in the Oval Office at 6.45am, and President Barack Obama typically arrived between 9am and 10am after working out.
Those hoping for a tell-all medical reveal from Trump's test may end up disappointed, according to Arthur Caplan, founding head of the Division of Medical Ethics at NYU School of Medicine.
"The President has the same right as any citizen in the United States to keep his medical information private. There's never been legislation requiring that he does otherwise."
The examination is merely a custom that has become norm for presidents in recent years, rather than a constitutional or congressional requirement.
Nonetheless Obama set the bar of expectation pretty high. His two-page medical summary released in March 2016 goes into remarkable details.
Everything from alcohol drinking habits — "occasionally and in moderation" — to his use of nicotine gum and cholesterol levels were spelled out in the official release.