Message Joe Biden left written for Donald Trump in the White House revealed

Joe Biden left a letter for Donald Trump during the presidential transition earlier this week on Monday (20 January).

The 78-year-old Republican leader revealed the letter on the day of his inauguration as he was signing executive orders from the Oval Office, finding it after pulling open a desk drawer when a reporter asked whether Biden left a note.

Biden's gesture in question follows a 36-year tradition of an outgoing president leaving a letter for their successor to find.

The letter in question, dated to Monday (20 January), read: "Dear President Trump, As I take leave of this sacred office I wish you and your family all the best in the next four years.

"The American people - and people around the world - look to this house for steadiness in the inevitable storms of history, and my prayer is that in the coming years will be a time of prosperity, peace, and grace for our nation."

Joe Biden left Donald Trump a letter during the presidential transition (Win McNamee / Staff / Getty Images)

It rounded off: "May God bless you and guide you as He has blessed and guided our beloved country since our founding."

"It could have been years before we found this thing," Trump said, holding up the letter with '47' written by hand on the outside envelope.

The day after he was sworn in as president on Tuesday (21 January), Trump said he appreciated Biden's note, calling it a 'very nice letter'.

"It was a little bit of an inspirational-type letter. Enjoy it, do a good job. Important, very important. How important the job is," Trump added.

During the inauguration ceremony, Biden could be seen catching up with Trump's youngest, Barron.

A clip of the exchange has captivated millions of viewers since Monday's ceremony, with many spectators wondering what on Earth the duo could have been chatting about so intimately.

Trump called Biden's note a 'very nice letter' (CHIP SOMODEVILLA / Contributor / Getty Images)

In the clip, the teenager can be seen at one point reaching for 82-year-old Biden's hand, before leaning in close to whisper something in his ear.

A lip reader has since come to the rescue with a suggestion for what words could have actually been exchanged during the interaction.

Offering an explanation for what took place between the former president and the current president's youngest child, expert witness forensic lip reader Jeremy Freeman told LADbible what he believes Biden said: "It's good to see you man," to which Barron responded with a slightly bizarre 'Exactly'.

Responding 'exactly' to someone saying 'it's good to see you' isn't exactly a normal response - something which could potentially explain why Biden looked so perplexed just moments after.