Tunisia international Lassad Nouioui has joined Celtic on a two-year deal, subject to international clearance.
Nouioui, 26, is the most recent addition to Neil Lennon's squad, following the arrival of defender Efe Ambrose, striker Miku Fedor and goalkeeper Lubos Kamenar.
Nouioui, who spent the last three years with Spanish side Deportivo La Coruna, told the club's official website: "I'm absolutely delighted to sign for Celtic.
"Celtic is a huge club with a magnificent history and a fantastic support. I know all about the wonderful atmosphere at Celtic Park and I can't wait to play there.
"I know that Celtic already has a great squad of players and I'm very much looking forward to joining up with my team-mates. And I hope to play my part in bringing success to the club.
"And, of course, I'm also looking to competing in the Champions League with such a great football club.''