The German 17 year old will officially join Leverkusen on January 1 but the Bundesliga side, who qualified for the knock out stages of the Champions League this week, have already announced the deal.
Brandt was initially set to leave Wolfsburg at the end of the season but Chelsea’s interest in the forward shocked the two German clubs into action sooner rather than later.
Chelsea have been intensely scouting in Germany, especially in the younger age groups, after the recent success of Bayern Munich, Borussia Dortmund and the national side.
“Julian Brandt is one of the most gifted youngsters in the German game,” Leverkusen general manager Rudi Voller told Deutsche Presseagentur.
“His signature is a great investment for the future of Bayer Leverkusen.”
Brandt is unlikely to feature in the Leverkusen first team this season but will join up with the squad in the summer to earn his place in Voller’s team.