Name that Carol- Day 1

So I have this little quiz for the run up to Christmas.

On random days between now and The Big Day I will be posting videos of my verbally challenged son* attempting to sing well known Christmas Carols - all you need to do is guess what it is he's singing.

Here's the first one:

Answers in the comments below please. I'll be picking a name at random at the end of the competition to give £20 to the charity of your choice.

(*Hey, don't feel bad, of course we are not laughing at him. We are laughing with him. And anyway - it's for a good cause).