He first made the bizarre declaration in January while defending himself against allegations he was unfit to be US president after publication of the book, Fire And Fury: Inside The Trump White House.

After the damning expose of his early days in office, he also went on to claim his two greatest assets were "mental stability and being, like, really smart".

During a press conference in Brussels on Thursday following a NATO summit, Trump was asked whether he would go on to change his mind and scrap the funding agreement in a tweet.

"No, that's other people that do that," he replied.

"I'm very consistent. I'm a very stable genius."

His stance on his intelligence does indeed appear to be consistent.

Australian Associated Press