Timo Werner said it was discussions with Frank Lampard that led to the decision to move to Chelsea this summer.
The blues activated Werner's $ 60 million release clause last month, which meant only personal information had to be agreed to secure the player's move to Stamford Bridge.
Liverpool were also reportedly interested in Werner's services, but Chelsea eventually won the race due to Lampard's influence, the player said.
Werner told Sky Sports: “The discussions with the Chelsea board were so good that I ultimately chose them.
"Frank Lampard in particular stood behind me and really wanted me to know that I can feel just as comfortable with Chelsea as with Leipzig.
“In conversations with me, the trainer often emphasized how much he wanted me, how much he valued me as a person. Of course, it's hard to give up an oasis of wellbeing like I've had in Leipzig for years, but you can only make a career if you take the next step.
“This season was the crossroads, otherwise I would have always stayed in Leipzig. I decided on something new and hope that my form will continue like this. "
Werner leaves RB Leipzig with good memories and praises Julian Nagelsmann, who has developed him into one of the strongest strikers in Europe.
"I was welcomed in Leipzig like never before in my career," he said about his time in the club.
“No matter which coach was responsible, I always had supporters here. Now there is Julian, who is a giant again and has improved me significantly. "
RB Leipzig finished the 2019/20 Bundesliga season third, while Chelsea are still struggling to maintain their Champions League qualifying position fourth for the next season in the Premier League.