The former flames hooked up over a flirty game of "Spill Your Guts or Fill Your Guts" where Kendall asked Harry which of his songs are about her and more probing questions.
It was perhaps the most twisted game of "Spill Your Guts or Fill Your Guts" in "Late Late Show" history as Harry Styles was filling in for James Corden and had on as his guest, his ex-girlfriend Kendall Jenner.
In other words, this was the perfect opportunity for them to ask probing questions about one another, perhaps things left unresolved when they called it quits. After all, if the other person didn't want to answer, all they had to do was take a big bit of some cod sperm and maybe down a 1,000-year-old eggnog.
"Is this cinnamon supposed to make this any better?" Kendall asked about that holiday delicacy, almost gagging just from smelling it.
At that point, Harry probably knew that he had her, as she could barely stand the smell of the drink, much less would she consider drinking it, right? Granted, the questions are random and secret even from the participants in the game, but isn't it fun to think that they knew when they had one another on the ropes.
This proved to be a very fun question for Harry, though, as he asked Kendall to rank her siblings from best to worst parents.
After a pause, Kendall said, "I feel like I could answer it."
"I feel like I could answer, it," Harry shot back, and the audience was suddenly on the edges of their seats. Just because they could didn't mean they would.
But apparently Kendall decided that if she qualified her statements enough by saying they're "all amazing," she could get away with actually doing this. But after she kicked things off by saying Rob is the best, she faltered.
Was she really going to do this? As she paused, Harry shot out, "Drink the eggnog."
And that was enough for Kendall to finish her train of thought ... out loud ... in public ... in front of cameras. Harry's face said it all as she rattled off, "Then it would be Khloe, Kim, Kylie--" Her voice cracked as she realized she'd just put Kourtney dead last.
"They're all amazing!" she shouted again, emphasizing that this was a ranking of great to great in her mind. But was it? Was it, really? Harry seemed to have a ranking, too. Would it match up?
The game continued with Kendall putting Harry under the microscope by asking him which of the tracks on his latest album are actually about her. "I'm dying to know this," she prefaced the question as he stared at a dish of cod sperm.
After poking around a bit with his fork, Harry started, "So I'd say track--" But then he stopped and got philosophical for a moment before finally deciding if he was going to reveal which tracks (if any) are about this ex, or take on some cod sperm.
Elsewhere in the clip, they had to consider eating bug trifle, giant water scorpion, a salmon smoothie, and Corden's favorite, bull penis. It was either those delicacies or Harry having to reveal if he's ever watched an episode of "Keeping Up with the Kardashians," or maybe rank his former One Direction bandmates' solo records.
Or perhaps Kendall was ready to reveal the most unlikable supermodel -- "I have the answer," she said quickly -- or the most surprising celeb who ever slid into her DMs.
You'll have to check out the clip for the fun banter, and to see which questions they opted to answer and which dishes they tried to stomach instead. When you do, you'll get to hear Harry get a little risque and philosophical talking about that cod sperm. "That is the question," indeed.