The Hamlet Project

I find it hard to believe that Osric doesn’t know that Hamlet already knows Laertes. I mean – first of all – Laertes may have newly returned to court but he’s been around. And Hamlet dated his sister. Which may have been meant to be a secret but really wasn’t.
But here’s Osric describing Laertes as if he’s a total stranger to the court. Is it possible that Osric is so rarely at court himself that Laertes is actually news to him? Or has he been instructed to praise Laertes by Claudius? Or can he just not help talking once he’s got started? I have met people like that – who would describe your own mother to you just because they got started on a descript-o-thon.