The Connel motorcycling ace will join Team D34G Racing as a substitute for Oliver Bayliss, who was injured in a crash earlier this year.
This means John can continue the FIM Supersport World Championship (World SSP) season that he started with Vince64 this weekend at the Tissot Aragon Round in Spain.
To date the 29-year-old has competed in nine rounds of this year's World SSP and most recently competed in the Pirelli French Round, sitting 16th in the overall rankings on 47 points.
John said: "A huge thanks to Davide Giugliano and the D34G team for giving me this opportunity to join them. I've been very impressed when seeing their team set-up, and their Ducati V2 looks incredible!
"I'll be looking forward to make my adaption to the bike as quickly as possible and look forward to the upcoming races. I'd like to also wish Oli Bayliss a speedy recovery, we hope to see you back on track soon."
D34G team team manager, Davide Giugliano said: "I would like to give our welcome to John within the team. He is a rider with plenty of experience, and we are happy to have him on board.
"We will do everything in our power to put him in the best position to do well and use all our skills, experience and expertise to help him adapt to the Panigale V2 955 as quickly as possible - given he's never ridden this bike before. We are looking forward to working together."
This development comes after it was announced last weekend that John was parting ways with Vince64, with three rounds of the World SSP season remaining.
Announcing John's departure, a Vince64 Racing Team statement said: “Unfortunately, difficult times have come and for reasons beyond our control we have decided by mutual agreement to terminate our sporting relationship for the 2023 World SSP season with immediate effect.
John had added: "Achieving a podium at our very first World Supersport race as a new team and project was something special.
“We’ve had some great times and some difficult times, it’s a shame, but for reasons outwith our control, we have made this mutual agreement to part ways with immediate effect."
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