The Netherlands Under-21 international spent the first half of the last season with Werder Bremen in the Bundesliga before a January switch to Club Brugge, where he won the Belgian First Division.
Chong will remain with United for the beginning of pre-season before joining up with the Blues at an agreed time ahead of their Championship campaign.
Having featured in 44 senior games across England, Germany and Belgium, the youngster already has an excellent range of experiences for a player of his age.
The Academy graduate, who was born in Curacao and has been capped six times by Netherlands Under-21s, won the coveted Denzil Haroun Reserve-Team Player of the Year award in 2019.