Borussia Dortmund adviser Matthias Sammer says Jude Bellingham must smarten up if he's to succeed at Real Madrid.
Bellingham has agreed to join Real this summer with the two clubs due to negotiate a fee for the England international.
Sammer believes the move has come too early for Bellingham, who he says isn't mature enough to handle the demands of being a big money Real Madrid signing.
He said, He'll have to mature quickly at Real.
"Obviously, a 20-year-old does some silly stuff off the pitch and sometimes on it too, which is completely normal growing up for him.
"If he were to stay in Dortmund, he would continue to mature slowly. If he were to join a club like Real, he will have to adapt faster and more completely. He will decide."