The 29-year-old Serbian is the first driver to commit to next year's second class. He will run with Campos, although his SEAT will officially be badged as a NIS Petrol Racing Team entry.
Borkovic, a European Hill Climb champion, finished third in the S2000 class of this year's European Touring Car Cup, taking one win and five podiums.
"This was not an easy decision and I'm glad to have taken it together with my team," he said.
"The fact that I will be driving alongside some of the greatest race car drivers, including a true legend like Sebastien Loeb, and will be able to compete in a world championship is a great achievement for me.
"I will take 2014 as an apprenticeship year to learn the tracks in view of 2015. I will do my best to achieve the best possible results, however whatever comes will make me happy."
Campos team manager Joan Orus told AUTOSPORT that he plans to run three cars in the Independents class next year, which will be open to models from this year's championship and will be rebranded as TC2.
"We are planning to run with three SEATs in that class," Orus confirmed, "and are in negotiations with four or five drivers at the moment."
Orus said 2013 regular Fernando Monje is "99 per cent" confirmed for TC2.
As AUTOSPORT revealed in early November, Campos will also run a 2014-spec Chevrolet Cruze for Hugo Valente.
Tom Chilton remains the only other man to have agreed a deal for an upgraded Cruze, although he has not yet confirmed which team he will run with.
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