The Dutch left-back returned to his homeland in October with AZ Alkmaar, where he made his top-flight debut last month in a 2-2 draw at Utrecht, and now joins fellow Eredivisie side ADO Den Haag on loan until the end of 2020/21.

Castillo signed for Chelsea from Ajax in the summer of 2016, having captained both the Amsterdam club and the Netherlands at youth level.

He helped our Academy win the Under-18 Premier League and FA Youth Cup during his first year with the Blues, which included completing the scoring in our 9-2 thrashing of Tottenham in the latter competition.

The next season he was again a regular as we retained the Youth Cup, as well as reaching the final of the UEFA Youth League with our Under-19s and scoring his first development squad goal in our Checkatrade Trophy quarter-final win over Oxford United’s senior side.

He then had his first loan in 2019/20, when he returned to Ajax and helped their Under-21s side finish fourth in the Dutch second division.

The 20-year-old will continue to gain top-flight experience with ADO Den Haag for the remainder of this season. They are currently 16th in the table.