Belgian defender Dedryck Boyata has left Celtic for German side Hertha Berlin on what is described as a long-term deal.
The 28-year-old was available on a free transfer with his contract at the Glasgow outfit expiring this summer.
The German club's sporting director Michael Preetz said: "We've had Dedryck in our sights for some time now and are fully convinced of his qualities, and we are confident that he is a real reinforcement for our defence."
Boyata moved to Celtic in 2015 from Manchester City.
He was involved in a row with then Hoops boss Brendan Rodgers at the start of this season, being sent to train with the development side after he missed a Champions League qualifier against AEK Athens in Greece when he claimed to be injured.
Boyata told his new club's website: "The club is ambitious and has goals that I stand by and I was very impressed by how Michael Preetz tried to talk to me and showed me a clear plan."
ga('create', 'UA-72310761-1', 'auto', {'name': 'pacontentapi'});
ga('pacontentapi.set', 'referrer', location.origin);
ga('pacontentapi.set', 'dimension1', 'By Press Association Sport staff');
ga('pacontentapi.set', 'dimension2', '196258aa-010c-4709-bccd-32403a28a6d7');
ga('pacontentapi.set', 'dimension3', 'paservice:sport,paservice:sport:club-news,paservice:sport:football');
ga('pacontentapi.set', 'dimension6', 'story');
ga('pacontentapi.set', 'dimension7', 'composite');
ga('pacontentapi.set', 'dimension8', null);
ga('pacontentapi.set', 'dimension9', 'sport:football');
ga('pacontentapi.send', 'pageview', { 'location': location.href, 'page': (location.pathname + location.search + location.hash), 'title': 'Boyata is Berlin bound'});