Goalkeeper Fraser Forster has completed a permanent £2 million move from Newcastle to Celtic after spending the last two seasons on loan at Parkhead.
"I want to win things as a team and improve as an individual, and I think I will be able to do that at Celtic.
"It also gives me a great opportunity to play in the Champions League if we get through the qualifiers. I really enjoyed my time in Europe last season, so I will be looking forward to it if it happens again.
"I enjoyed last season as a whole and we have a great young squad here. The players and the coaches make it an enjoyable place to be and I like being a part of this team."
Forster's move was sealed after Celtic failed in a move to bring Scotland international goalkeeper Craig Gordon to the club when he was unable to agree terms on a three-year contract.
He had previously spent spells on loan at Stockport, Bristol Rovers and Norwich.