Mardenborough will compete in Horner's Arden International team in GP3, the series being a key rung on the ladder to Formula One.
Last season Russia's Daniil Kvyat won the GP3 title with Arden and will now compete in F1 this year with Toro Rosso.
Mardenborough's rise is unusual because up until two and a half years ago he had never seriously competed in motorsport.
Instead, the 22-year-old from Darlington beat 90,000 other hopefuls in the virtual gaming GT Academy programme run by Nissan and Sony.
Nissan then helped Mardenborough develop his talent on the race track as he has since competed in GT cars, Le Mans prototypes and single-seaters.
Following a successful test with Arden in November, after competing in the British and European Formula Three Championships last season, Mardenborough is now effectively part of the Red Bull stable.
Alongside driving in GP3, Mardenborough will also be involved in Red Bull's bespoke driver development programme.
Mardenborough said: "I feel ready for GP3.
"I've prepared well and I have all the right people around me to help my development so I can fully focus on my racing.
"This season is my opportunity to impress more people in the sport who make the decisions on who makes it into F1 and who doesn't, and I'm going to give it my best shot."
For Red Bull, it is the first time they have taken on a 'gamer' rather than someone who has followed a more natural path from a young age.
Red Bull Racing's driver development manager Andy Damerum said: "We have been tracking Nissan's innovative approach to motorsport, and in particular GT Academy that challenges the status quo of motorsport.
"The traditional route to F1 of karting and single-seaters is a tried-and-tested success, but Nissan and PlayStation have gone down a very different road and started to find some very talented drivers who have been doing all their practising on a games console.
"I'm very interested to see how Jann fares on our programme and in GP3 this season, and I look forward to taking him under the Red Bull Racing wing to further progress his career."