Well, C. S. Lewis certainly taught that we can become gods. As to whether the type of gods Lewis discusses is the same as the Mormon view of our potential god-hood, probably not. However, even the Mormon concept of what it means to become gods is not clear, since the applicable revelation (found in the Doctrine and Covenants, section 132) just says we shall be "gods", without giving a lot of particulars. (Although, I should say that the typical Mormon view is that we will be gods in the sense of being able to create our own spirit children who will have the same relationship to us as we do to our Father in Heaven. We, however, will still be subservient to our own Father in Heaven.)

What Lewis has in mind when he says "[God] will make the feeblest and filthiest of us into a god or goddess" (see below), I will allow the reader to decide. What follows is from his book, Mere Christianity (page numbers are from the edition I own).

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[Christian writings] say that Christ is the Son of God (whatever that means. They say that those who give Him their confidence can also become Sons Of God (whatever that means). [Book 4, chapter 1, paragraph 8 (pg 137)]

Now the point in Christianity which gives us the greatest shock is the statement that by attaching ourselves to Christ, we can "become Sons of God." One asks "Aren't we Sons of God already? Surely the fatherhood of God is one of the main Christian ideas?" Well, in a certain sense, no doubt we are sons of God already. I mean, God has brought us into existence and loves us and looks after us, and in that way is like a father. But when the Bible talks of our "becoming" Sons of God, obviously it must mean something different. And that brings us up against the very centre of Theology. [Book 4, chapter 1, paragraph 10 (pg 137-8)]

One of the creeds says that Christ is the Son of God "begotten, not created"... Now this is the first thing to get clear. What God begets is God; just as what man begets is man. What God creates is not God, just as what man makes is not man. That is why men are not Sons of God in the same sense that Christ is. They may be like God in certain ways, but they are not things of the same kind. They are more like statues or pictures of God. [Book 4, chapter 1, paragraphs 11 and 13 (pg 138)]

[With] man, the highest of animals, we get the completest resemblance of God which we know of... Man not only lives, but loves and reasons: biological life reaches its highest known level in him. But what man, in his natural condition, has not got, is Spiritual life--the higher and different sort of life that exists in God. We use the same word life for both: but if you thought that both must therefore be the same sort of thing, that would be like thinking that the "greatness" of space and the "greatness" of God were the same sort of greatness... a man who changed from having Bios [Biological life] to having Zoe [Spiritual life] would have gone through as big a change as a statue which changed from being a carved stone to being a real man. [Book 4, chapter 1, paragraph 14 and 15 (pg 139)]

...some people think that after this life, of perhaps after several lives, human souls will be "absorbed" into God. But when they try to explain what they mean, they seem to be thinking of our being absorbed into God as one material thing is absorbed into another. They say it is like a drop of water slipping into the sea. But of course that is the end of the drop. If that is what happens to us, then being absorbed is the same as ceasing to exist. It is only the Christians who have any idea of how human souls can be taken into the life of God and yet remain themselves-- in fact, be very much more themselves than they were before. I warned you that Theology is practical. The whole purpose for which we exist is to be thus taken into the life of God. Wrong ideas about what that life is, will make it harder. [Book 4, chapter 2, paragraphs 2 and 3 (pg 141)]

You remember what I said ... about begetting and making. We are not begotten by God, we are only made by Him: in our natural state we are not sons of God, only (so to speak) statues. We have not got Zoe, or spiritual life: only Bios, or biological life which is presently going to run down and die. Now the whole offer which Christianity makes is this: that we can, if we let God have His way, come to share in the life of Christ. If we do, we shall then be sharing a life which was begotten, not made, which always has existed and always will exist. Christ is the Son of God. If we share in this kind of life we also shall be sons of God. We shall love the Father as He does and the Holy Ghost will arise is us. He came to this world and became a man in order to spread to other men the kind of life He has-- by what I call "good infection." Every Christian is to become a little Christ. The whole purpose of becoming a Christian is simply nothing else. [Book 4, chapter 4, paragraph 10 (pg 153)]

Christ says "Give me All. I don't want so much of your time and so much of your money and so much of your work: I want You. I have not come to torment your natural self, but to kill it. No half-measures are any good. I don't want to cut off a branch here and a branch there. I want to have the whole tree down. I don't want to drill the tooth, or crown it, or stop it, but to have it out. Hand over the whole natural self, all the desires which you think innocent as well as the ones you think wicked-- the whole outfit. I will give you a new self instead. In fact, I will give you Myself: my own will shall become yours. [Book 4, chapter 8, paragraph 4 (pg 167)]

When He said "Be perfect," He meant it. He meant that we must go in for the full treatment. It is hard; but the sort of compromise we are all hankering after is harder-- in fact, it is impossible. It may be hard for an egg to turn into a bird: it would be a jolly sight harder for it to learn to fly while remaining an egg. We are like eggs at present. And you cannot go on indefinitely being just an ordinary, decent egg. We must be hatched or go bad. May I come back to what I said before? That is the whole of Christianity. There is nothing else... God became Man for no other purpose. It is doubtful, you know, whether the whole universe was created for any other purpose. [Book 4, chapter 8, paragraphs 9 and 10 (pg 169-170)]

I find a good many people have been bothered by ... Our Lord's words, "Be ye perfect." Some people seem to think this means "Unless you are perfect, I will not help you"; and as we cannot be perfect, then, if He meant that, our position is hopeless. But I do not think He did mean that. I think He meant "The only help I will give is help to become perfect. You may want something less: but I will give you nothing less." ... The job will not be completed in this life: but He means to get us as far as possible before death. [Book 4, chapter 9, paragraphs 1 and 8 (pg 171,174)]

The command Be ye perfect is not idealistic gas. Nor is it a command to do the impossible. He is going to make us into creatures that can obey that command. He said (in the Bible) that we were "gods" and He is going to make good His words. If we let Him-- for we can prevent Him, if we choose-- He will make the feeblest and filthiest of us into a god or goddess, dazzling, radiant , immortal creature, pulsating all through with such energy and joy and wisdom and love as we cannot now imagine, a bright stainless mirror which reflects back to God perfectly (though, of course, on a smaller scale) His own boundless power and delight and goodness. The process will be long and in parts very painful; but that is what we are in for. Nothing less. He meant what He said. [Book 4, chapter 9, paragraph 11 (pg 174-175)]