The former Arsenal, Leicester City and Cardiff City defender put pen to paper for the Hoops this afternoon (Wednesday).
The London-born full-back most recently played for Yeovil Town in the English Football League One.
Stephen Kenny explained that Gilbert is exactly the type of player he was looking for.
He said: “Kerrea is only 24, but has played a lot of games in England including 34 games for Leicester City in the Championship during his one season loan period with them. We needed to add a right-back to the squad, and Kerrea is a very good addition for us. He is quick and is a very good defender.
“Despite his still young age, he has a lot of experience and I think his best years are very much ahead of him. We have added quality and ability with this signing. He has trained with the team for the last few days and he is hungry to well and make an impact with us this season.”