Celtic have clinched deals to bring Manchester City striker Georgios Samaras and Japanese midfielder Koki Mizuno to Parkhead.Greece international Samaras, 22, has joined on loan from City until the end of the season, with a view to the deal becoming permanent in the summer. Mizuno, also 22, has become a permanent signing, agreeing a three-and-a-half-year contract with Celtic. Samaras is eager to be involved for his country at Euro 2008, where Greece will defend their title. However his first-team opportunities with City have been limited since Sven-Goran Eriksson's appointment in the summer. The 6ft 4in frontman was a £6million signing from Heerenveen in 2006 but has failed to make the impact expected of him in England. Celtic boss Gordon Strachan will be hoping Samaras gives Greece coach Otto Rehhagel plenty of food for thought in the coming months, as he looks to help the Hoops overhaul leaders Rangers and win a third successive Scottish league title. He will compete with Jan Vennegoor of Hesselink, Scott McDonald and Chris Killen for selection. Celtic secured a work permit for Mizuno after convincing an appeals panel he was an exceptional case, despite winning just three caps for Japan so far. He joins fellow Japan midfielder Shunsuke Nakamura at Celtic after leaving the J.League.