Chelsea have tied Nathan Ake down to a new five-year contract before sending the defender on loan to Watford.
The centre-back moved to Stamford Bridge as a 15-year-old and has featured on 12 occasions for the club, including playing in the UEFA Champions League and Europa League.
Ake, who spent a month on loan at Championship side Reading last month, has now committed his future to the Premier League champions.
The 20-year-old will continue his development at Vicarage Road, though, having agreed to join Watford on a season-long loan.
Watford, promoted from the Championship last term, have been busy during the transfer window with the likes of Valon Behrami, Miguel Britos and Jose Holebas among those to have joined Quique Sanchez Flores' side.
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