King’s progression up the Ginetta ladder will come with Elite Motorsport as they also make their Supercup debut.
The 17-year-old competed in the Juniors for two seasons, with a strong debut campaign featuring two victories.
While he couldn’t challenge for the title in his second year, nine podiums including one win gave him a top six points finish.
Elite are embarking on their first Supercup season alongside a large six-car entry into the Ginetta Juniors.
“I’m delighted to be moving up to the Supercup and I’d like to think I can be on the pace from the start,” said King.
“Being a new team in what is a very competitive championship, we will all be learning together, but I have complete faith in the people around me to get the job done.
“I know the Elite Motorsport guys will not stop working until we reach the ultimate goal, which is winning.”