The Irishman leaves Norwich City after seven years to join Brendan Rodgers’ side in an initial deal worth £8.5 million, plus another £1 million in add-ons. The Canaries have also included a 15 percent sell-on clause in the deal.
Idah has signed a long-term contract at Celtic Park and is City’s second high-profile departure after Gabriel Sara joined Galatasaray earlier this summer.
The striker made 116 appearances for Norwich, mostly as a substitute, and scored 17 goals, including notable last-minute strikes against Hull and Bristol City last year.
Speaking to City’s channels about his departure, sporting director Ben Knapper said: “Adam leaves us with our best wishes. He has a great opportunity to continue his development at Celtic.”
“The Academy staff have been very proud to witness Adam’s development from youth player to senior squad and finally to full Republic of Ireland international. So many people here have had a hand in his journey and he and everyone else should be really proud.
“Everyone at Norwich City wishes Adam all the best for the future.”
The striker has made no secret of his desire to return to his boyhood club after a successful loan spell in the second half of the season and is delighted to now fulfil his dream of becoming a permanent player at Celtic.
“I think everyone knew where I wanted to go. For me it’s great and I’m happy to be back,” Idah said via Celtic’s official channels.
“From the first few days here, when I was first loaned out, I wanted to play for Celtic.
“It was incredible, scoring all those goals, being with the boys and seeing those amazing fans week after week was incredible.”
“I have never experienced anything like this before and I am just so happy to be back.
“I’ve always wanted to play for Celtic and last season was obviously fantastic. To now come here and be fully part of the team and this club is incredible for me.
“Everyone at home, all my family and friends, they all wanted me to come back to Celtic, myself included. It’s great and I’m just so happy to be here.”
This view is shared by Celtic head coach Rodgers, who praised the club’s management for negotiating a deal with the Canaries that would allow Idah to return permanently.
“We are delighted to welcome Adam to Celtic on a permanent basis and are delighted that he has agreed to this new five-year contract with the club.
“The club has done a great job in securing this long-term contract. We are investing in a player of real quality who will be crucial for us over the next few years.
“He is a player who has already given us so much, putting in fantastic performances for us on loan and really making a difference for the club and our fans last season.
“Adam has fantastic qualities and he is a dynamic, hungry, committed player who can really make a difference.
“The most important thing is that Adam feels at home at Celtic. He has a great love and passion for the club and I know he will give everything to bring success to our fans again.”