The YouTubers have met in the ring twice before, with the first amateur bout in 2018 declared a draw and the second professional bout in 2019 going in KSI's favour following a split decision from the judges.
Now, it seems the influencers may lock horns once again - in what capacity exactly, we don't yet know.
KSI - or Olajide Olayinka Williams Olatunji, as he's less well known - shared an image on social media in which the pair can be seen in the ring throwing punches at each other.
The post was captioned: "The KSI Show - July 17th."
So, what exactly can we glean from this? At this point, we can only really speculate - which people have done in their droves.
Presumably, they're not having a proper fight with less than a week's promotion, but then again the growing scene of influencer boxing has rarely abided by the normal customs of the sport.
For now, people have a few theories about what we should expect on Saturday:
What we definitely know will happen on Saturday is The KSI Show, which starts at 8pm BST.
Another thing we know is KSI is very good at making money, reflected by the fact it will cost you £15 ($20.75) to buy a ticket for the show.
A summary reads as follows: "The KSI Show will be a once-in-a-lifetime experience featuring first ever performances of tracks from All Over the Place, a retelling of the story of KSI, past, present and future with special guests and key characters throughout his journey and more.
"Let KSI take you on an adventure through his world. Get ready for thrills, laughs and lots of surprises."
You can buy a ticket here.Featured Image Credit: Twitter/KSI