The 27-year-old, pictured, impressed for the Blues in pre-season after signing from French outfit ES Viry Chatillon and had been training with Mark Bentley's squad in recent weeks.
In a statement announcing his signing on Ryman League and Essex Senior League forms on Thursday night, officials said Kiaku would feature for the reserves against Sawbridgeworth Town on Friday in a bid to boost his fitness but would also be available for Saturday's First Qualifying Round clash against Biggleswade United at Mill Field.
Kiaku also played professionally at French National League sides Uzès, Paris FC, Stade Laval and Le Mans and Blues coach David Raven told supporters he was looking forward to seeing Kiaku taking his chances English football.
Raven said: "It can be a slow process as we have had to wait for the French FA to give him the all-clear to play. With the relocation to England, Charles has not been able to train but he has settled into the squad well and just needs playing time to get the match fitness and sharpness back."
He added: "Hopefully it won't be too long before we see him making his mark on the Ryman Premier."
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