In early 2015 it was announced that Delecour would participate in FIA's new R-GT Cup series for GT cars in the World and European Rally Championships with a Porsche 911 run by Tuthill team. Rallies include Monte Carlo, Ypres Rally, Rally Germany, Rally Valais and the Tour of Corsica. In Monte Carlo, Delecour won his class and finished on 23rd place in overall results with his Porsche. In Ypres Rally, Delecour finished second in RGT Cup class. He finished second again in RGT cup event in Rallye Deutschland, but his overall position was 53rd after suffering from problems, including going off in the second day of the rally. Delecour won the next event, Tour de Corse, and secured the victory of FIA R-GT championship.