Benoit Badiashile will wear the number four for Chelsea, after completing his move from Monaco earlier this week.
The French defender signed a contract that runs until 2030 with the Blues and could be set for a Chelsea debut against Manchester City in the FA Cup on Sunday.
Benoit opted for the vacant number four jersey, which was last worn by Andreas Christensen, and trained with his new team-mates for the first time earlier this week.
Meanwhile, two more Blues have been handed squad numbers by head coach Graham Potter.
David Datro Fofana, who finalised his move from Molde earlier on Saturday, will also hope to be involved at the Etihad this weekend and he has been handed the number 27 shirt.
Goalkeeper Gabriel Slonina, who has returned from a loan spell at Chicago Fire, has also been given a squad number for the remainder of the season. He is our new number 36.