After training with the Crewe team this summer, Christian Mbulu has now joined the club.
The 23-year-old central defender has agreed a short-term deal with the Alex.
A former Millwall defender, Mbulu joined the Lions in 2015 after helping non-league Brentwood Town to promotion.
Whilst at Millwall, he enjoyed a loan spell with National League side Braintree Town before a successful trial saw him earn a contract with Motherwell in the summer of 2018.
He made six appearances for the club in the Scottish Premier League last term, before spending the summer training at Reaseheath.
The defender featured in several pre-season games for the Alex and will now be looking to help Crewe build on their successful start to the season.
Mbulu will wear the number 30 shirt whilst at Gresty Road.