Jimmy Fallon dared to rumple Donald Trump's perfect hair during interview.

It’s the interview that’s ruffling more than just one presidential candidate’s hairpiece.

Comedian and late night host Jimmy Fallon used his onscreen time with Republican candidate Donald Trump to do something “that’s just not presidential”.

Tonight Show viewers watched as Fallon ruffled the 70-year-old Republican’s helmet of carefully hairsprayed hair.

The move was not unprompted but came after a careful negotiation between the pair.

Fallon reminded viewers of the potentially changing status of his guest before he made a cryptic request.

"The next time I see you, you could be the president of the United States," he said.

"I just wanted to know if there’s something we can do that’s just not presidential, really, something that we could do now that we're both just civilians."

Trump leaned back and pulled a face before expressing his displeasure.

"I'm not liking the sound of this," he said.

Fallon, undeterred and grinning, went ahead to make his play.

"Can I mess your hair up?" he asked.

Trump gave in after briefly apologising to the people he would meet in his next press circuit.

A drum roll began and the late night host leaned in to violently toss around the 70-year-old's strawberry blonde locks.

Trump looked pleased as punch in the aftermath, gently tapping down his new Marie Antoinette-esque do.

I'm not sure we'd see Leigh Sales or Carrie Bickmore reaching out to our political candidates.

(Let's all take a moment of quiet thanks.)

Feature image via NBC/Screenshot.