"The move to Germany is really exciting for me and I can play in the Champions League with Bayer Leverkusen," said Hudson-Odoi.

"That combination is really attractive and I'm keen to get to know the club, the fans and the Bundesliga."

The German club's hierarchy are expecting an instant impact from the 21-year-old.

"He has everything to be able to help us immediately," Bayer Leverkusen's sporting managing director Simon Rolfes said.

"This will give our attacking game another special component. We're very happy this transfer has gone through."

Chelsea have the option to recall Hudson-Odoi in January.