South Africa's Kelvin van der Linde, 18, will defend his 2014 GT Masters' crown as he races for Audi Sport in 2015.He will once again race a Audi R8 LMS Ultra in Germany’s premier sports car series, which comprises of eight rounds and includes races in Holland and Belgium. According to Audi, he will compete in selected endurance races.Van der Linde will relocate to Germany in Feb 2015 in preparation for the opening round at Oschersleben on April 24.'SACRIFICES PAYING OFF'He said: "A contract with Audi Sport is another big step forward, and an important development in my objective to make a career out of motorsport. I’m privileged that Audi and VW Group as a whole have placed such faith in me in recent years, and I look forward to driving for them in 2015 - and beyond. "I’ve worked extremely hard to reach this point in my career, and my family and I have made many sacrifices on many levels. I’m thrilled that it is all paying off."Van der Linde’s motorsport career started in karting when he was eight. He graduated to sedan racing and won the Engen Polo Cup title when he was 16. This earned him a drive in the 2014 Volkswagen Scirocco Cup in Germany which he went on to dominate, winning the title. YOUNGEST SERIES CHAMPIONThe prize money Van der Linde earned made it possible for him to secure an Audi R8 seat in the GT Masters series as a Junior driver with Prosperia C.Abt Racing (sharing a car with Rene Rast), one of Audi’s customer teams. Victory alongside Rast in 2014 made him the youngest-ever series champion – this despite writing Matric at the same time.Van der Linde was also the youngest recipient yet of the Driver of the Year award for the 2014 International Automobile Federation’s (FIA) Young Driver Excellence Academy, an initiative to identify and nurture young driver. 'DREAM COME TRUE'Van der Linde said: "I'm already looking forward to 2015's challenges – GT Masters is very competitive with many of the big automotive brands using it as a platform to promote their sports car lines. "The immediate objective therefore is to defend the title for Audi. Who knows, a successful season could lead to an Audi seat in LMP1 endurance racing or DTM in the future. Either would be like a dream come true, but I am just happy to be where I am right now, and I’m loving every moment."