The young Chelsea prospect has been in excellent form for the Hornets this season.
Aké has impressed at left-back for the Hornets after joining the newly promoted team on loan last summer and Quique Sanchez Flores wants him to be a part of the club's future.
His performances have helped his team stay out of relegation trouble all season long, and have been a major contributing factor in them having the joint 5th best defensive record in the league.
Watford have kept six clean sheets with Aké in the side with him averaging 2.61 clearances and 0.26 blocks per game.
He has become renowned for his impeccable tackling. His perfect timing in the challenge enables him to compensate for his sometimes poor positional sense, which is still under improvement. That will get better with experience.
He has also proved how versatile he is as a player. When playing for Chelsea's youth ranks, he operated in a wide-left attacking role. The transition to left back has been seemless.
With Watford impressing this season, not only will they do well to hold on to the likes of Try Deeney and Odion Ighalo, but also in making Aké's stay a permanent one.