Spaniard Siso Cunill will join KTR's Formula Renault 3.5 team for the remainder of the season.
The Belgian squad had been left with two vacant seats following the departure of Guillaume Moreau and Daniil Move after the fifth round of the championship at the Hungaroring last month.
The 17-year-old has been racing for Jenzer Motorsport in the Formula Renault Eurocup and Italian championships so far this season.
KTR have yet to fill the second seat, but hope to make an announcement by the end of this week, ahead of the next round at the Nurburgring next weekend.
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