“I was first told at the weekend that there was interest. You never know how much to believe in that, but as soon as I was told I had permission to speak to the club I was over the moon and just desperate to get it finished.
“I’ve been a supporter all my life, something I got from my dad. It might sound a bit sad saying it’s a dream come true, but it really is and it will be brilliant to play at a place like Celtic Park.
“My dad has a lot of experience. He’s had his career and he’s pushed me in the right way. When he found out as well he was dead keen for me to sign.
“It’s a chance for me. It’s going to be tough, it’s going to be a challenge, but it’s one I want.”
Ryan, 20, will return to Inverness on loan for the remainder of the season, but Celtic have the option to recall the forward in January.
The playmaker sees a return to John Hughes’ side on a temporary basis as a positive thing and is looking forward to maintaining his fitness and form through game-time with the club.
“I know it’s going to be a step up, but I have to challenge myself and I wouldn’t have signed if I didn’t think I was up for that challenge.
“It’s game-time and it keeps me fit and it’ll keep me in the best shape I can when I come to Celtic. There are a lot of targets we’re trying to hit at Inverness so that’s my short-term plan.
“John Hughes has been superb. I don’t know if him being an ex-Celtic player has helped, but he had a word in my ear before Saturday’s game just to put it at the back of my head.
“I just can’t wait to step out at Celtic Park for the first time.”