The 19-year old Welsh international has signed a four-year deal with the Glasgow powerhouse but before he left Cardiff, Manchester City striker Craig Bellamy, who was on loan at his hometown club, told Matthews that life will be great if he can quickly become a fan favourite.
And Matthews also admitted he was looking forward to being a part of such a big rivalry as the Old Firm with Rangers.
"The only real derby we have is Swansea. That's a massive derby but I think this one tops it.
"I don't think I have been to a game where the atmosphere was so good. I couldn't hear myself speak."