The two leaders have exchanged a barrage of provocative taunts, Trump calling Kim "rocket man'', threatening "'fire and fury'' and to "totally destroy North Korea", Kim vowing to "tame the mentally deranged US dotard with fire" before the pair started comparing the size of their nuclear buttons.
The bluster and bravado has been a boon for satirists and cartoonists the world over, who have portrayed the two in the most unflattering ways - as babies throwing their (nuclear) toys of the cot, mad men with crazy hairdos to match - but unnerving for the "adults in the room'', and onlookers the world over.
So the sudden apparent U-turn is welcome, but unsettling. Can we trust what we are witnessing?
It will certainly not be easy to craft an agreement that allows both impetuous and narcissistic leaders to walk out with their heads held high. Indeed, Trump has already threatened a temper tantrum - the promise of walking out - if he deems the meeting a waste of time.
Yet, North Korea has made a powerful nuclear capability statement, and is crippled by sanctions. The US leader has not made strides on the domestic agenda he promised, has ruffled international feathers and turned his own administration into a laughing stock. A landmark agreement he could claim as his own would be a global PR win (even - in an irony not lost on most, as he simultaneously threatens to pull out of the Obama administration's Iran nuclear deal).
It could all so easily backfire if these two unpredictables push each other's buttons, though. The path ahead may be lined with good intentions, but it is also fraught with the potential for distrust, miscommunication, misunderstanding, wilful misinterpretation and the sort of militant misanthropy that makes the world a very small and dangerous place.
The summit - if it even happens - offers at once a hopeful, fascinating and terrifying prospect.