Left-back Cheick Keita joined Blues from Italian Serie B side Virtus Entella on 19 January 2017.
Keita penned a three-and-a-half-year deal. plus a one-year option with the Club for an undisclosed fee.
An athletic and pacy player who likes to get forward, Keita will provide an additional attacking threat on the flanks.
Born in the French capital, Paris, Keita is a product of the French Football Federation's centre of excellence in Clairefontaine.
As a youth player, he spent three years with AS Monaco, before being released by the French top flight club.
Keita moved to neighbouring Italy in 2014 where he linked up with Entella and went on to make 67 appearances.
Keita made his Blues debut in the 1-0 win over Fulham on February 4, 2017, in a Sky Bet Championship fixture at St. Andrew's.