The much-hyped grudge match between the two social media stars takes place in America next month, with the rivals announcing they have turned professional for it.
It will be the second time the pair will have fought each other, with the rematch taking place around a year after a similar bout in Manchester last year drew huge numbers.
A press conference to promote the clash, which is being promoted by Eddie Hearn, ended in farce on Monday night with the pair flinging crass insults at each other throughout.
So ahead of the November fight, here's everything you need to know about the KSI vs Logan Paul rematch.
Why are they fighting?
The pair fought last year, in what was expected to be the climax of an ongoing feud between the pair.
But that fight ended in a draw, and with neither side able to claim victory, they have decided to sign on for a rematch this year.
Who is on the undercard?
While the fight undercard is yet to be announced, Billy Joe Saunders will be making a return to the ring to defend his super-middleweight title.
Rising star Devin Haney is also heavily rumoured to be fighting.
Can I get tickets?
You can, and you can get them here. They range from around £33 to more than £644.
They are expected to go quickly after last year's event was a sell out.
KSI vs Logan Paul rematch date and time
The pair will showdown at the Staples Centre in Los Angeles, California on November 9.
It is expected to start around 9pm in the US, which will be 5am on Sunday, November 10 in the UK.
Will there be a live stream?
The fight will be streamed on subsription service DAZN.
It will also be available on Sky Sports Box Office in the UK for £9.95.
What are the odds?
The odds according to Oddschecker:
Logan Paul 4/5
What happened at the press conference?
Last night's press conference descended into chaso with both fighters hurling outrageous and bizarre insults at one another.
Logan mocked KSI for having a small penis by bringing on a pack of condoms for "little peckers", insulted him for having five abortions, threatened to kiss his "mum on the cheek" and give his opponent a "wet willy on his belly button".
At one point the American also made a bizarre reference to World War II, saying: "All the support we gave you in World War II and this is how you return the favour?
"Winston Churchill would be ashamed."
KSI hit back by saying: "I have no respect for Logan Paul, I can't wait to finish you off.
"You used a dead dog for views, a dead guy for views; is there anything you won't use for views? Maybe your career once I'm done with it.
"November 9th you'll see all your boxing ability is going to go out of the window and you are going to be finished. I'm going to finish him, I'm going to make him suffer slowly."
At one point, the crowd at the press conference chanted other slurs such as "suck your mum" and another about Donald Trump.