I would describe your cat as a blue domestic longhair. He is so handsome!
We know from looking at your cat that both his father and mother carry the recessive genes for solid, dilute (blue), and long hair; however his father might have been any color or hair length (for example he might have been a short haired tabby, etc).
Your cat doesn't appear to have extreme features that would suggest specific breed ancestry. Most cats are not any particular breed.
While we await the experts arrival, I'll make a suggestion right away....his collar appears to have a buckle/fastener that can only be released by a person.
That kind of collar is not used any longer by people who really know about cats.....because it can result in very serious and/or fatal injury to the kitten/cat. It can happen if it gets caught up in something, and the kitten can be severely injured or even strangled.
Today (for people who even use collars), a quick-release or "breakaway" type is the norm.
And, while he may have worn it for a long time already without an issue..... well, you should know that even here on this forum, we have read horror stories from people who experienced accidents like this.)
It was hard to write all that because.....well, WOW, just WOW.....what a stunner he is! HE will stand out in any c̶r̶o̶w̶d̶ clowder! (which is why you might perhaps also drop a pic in this thread: Lets See Your Majestic/distinguished Pose!)
Oh, I see that one of our most distinguished experts has come by......
Well, one issue is still outstanding...........you should know that no cat, not a single one can remain anonymous here So, what's this lion king's name ?
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He is so cute! I would describe him as a blue Domestic Longhair. Domestic Longhairs are the landrace cat breed. You could also describe him as a Maltese cat.