And in his explosive autobiography, Drogba reveals how a furious Mourinho accused him of lying over the trip.
In C'Etait Pas Gagne, Drogba wrote: "Jose took the phone and put it on loudspeaker and said: 'OK, seeing as we are not kids we are going to talk. I trusted you - I've done everything for you and there you are telling me you're going to the dentist in Paris when in fact you're in Milan talking over your transfer. You lied to me. You didn't keep your word. Have you been badly brought up or what?'"
Mourinho was so angry that he ordered Drogba to train with the Blues reserves.
And the former Marseille man underwent the humiliation of turning out for the second team against West Ham the following night.
Drogba made up with his mentor shortly afterwards and the row turned out to be the making of him.
He went on to score 34 goals in the 2006-07 season - the first Chelsea striker to breach the 30 mark since Kerry Dixon in 1985.
