Celtic have signed Cameroon full-back Jean-Joel Perrier-Doumbe on a six-month loan from French club Rennes.
Jean-Joel Perrier-Doumbe has had injury problems
The Scottish champions also have the option to sign the 28-year-old permanently for a further two years.
Perrier-Doumbe told Celtic's website: "I know that they are a massive club with a great history and support.
"It means a lot to me to be joining a club which not only is doing well in the league but is still involved in the Champions League."
BBC Sport understands that Celtic will pay the French club £400,000.
Perrier-Doumbe trained with his new team-mates on Tuesday, but the transfer was held up by the need for international clearance.
Celtic are looking to strengthen their defence after injuries to Bobo Balde, Gary Caldwell and Mark Wilson.
Perrier-Doumbe is not cup-tied for the Champions League, unlike recent signing Steven Pressley.
"He can play at both left-back and right-back and he is a strong, powerful defender," said agent Willie McKay when the player began a two-day trial with Celtic on 12 January.
"He is an experienced player who has played at two World Cups with Cameroon and he has been unlucky this season with injury.
"He almost joined Middlesbrough last summer before he picked up an injury."