Drogba believes that Lukaku has the potential to become one of the greatest strikers in the Premier League.
He said on Sky Sports' Goals on Sunday: "He's very strong. He has been working a lot to improve that and to make sure that his strength and technique can work together in this league. I remember he technically had a lot to work on when he first signed at Chelsea. He has got his reward for that. I texted him a few weeks ago when he gave a pass to Arouna Kone with his left foot and told him 'the day you do that with your right foot…'.
"He is scoring goals with his left foot, right foot head. I told him he is on the way to becoming one of the greatest in this league. He is an athlete. I'm not surprised [Chelsea let him go] because Chelsea is very competitive and for him to play and get the confidence he has now he had to go and play for a team like Everton where they play a lot for the striker.
"Even if you don't play well in one game you will still play in the second one. At Chelsea it was very difficult; if you don't perform you are dropped."