Referencing a dll created in VS 2005, in VS 2003

Question

Can it be done? I have a dll which was written in VS 2005, by someone else. I need to integrate that into one of my projects in VS 2003, how do I go about doing that? When I try and reference it I get an error stating that its not a valid assembly or COM component, and that I can't reference it. Any input would be appreciated. Thanks