The worlds No1 and 2 brushed past their respective semi-final opponents – Taylor Fritz and Novak Djokovic – both with 6-4 6-2 victories.
Alcaraz admitted coming into the new exhibition that he was not fully fit, having injured his ankle in Tokyo against Sebastien Baez.
Sinner, meanwhile, gave Dutchman Talon Griekspoor a walkover in the second round of the Shanghai Masters after he suffered with severe cramp mid-match thanks to the extreme heat.
The pair’s most recent meeting came in the US Open final, where Alcaraz defeated the Italian in four sets.
Before that, Sinner had forfeited the final of Cincinnati when 5-0 down to the Spaniard due to illness.
Alcaraz dominates the pair’s head-to-head, leading 10-5, although Sinner usurped the 22-year-old at Wimbledon this year to earn a maiden title on the grass.
What time is Carlos Alcaraz vs Jannik Sinner?
The final of the Six Kings Slam will take place on Saturday, October 18.
The match won’t start until at least 7pm BST, scheduled after the third-place encounter between Fritz and Djokovic, which kicks off at 5pm BST.
How to watch Carlos Alcaraz vs Jannik Sinner
Live stream: This tournament is being exclusively streamed on Netflix. It isn’t a pay-per-view event, and those with a Netflix subscription will be able to stream it live.
