Using a .Net object in VBA

[Boknaai]

I've written a .Net class library (compiled as a .dll) in C#. I now want to call this object from an Excel spreadsheet in the VBA code. I have tried adding a reference to the dll (tools > references > browse in the Visual Basic editor) but i get a message saying "can't add a reference to the specified file". Could somebody please suggest how i can go about doing this so i can use this object.

Thanks!