Create functions (in a DLL) callable from C# and Delphi projects ?

Question

Hello. I need help here, been stuck for some hours looking around on the net without luck. Here is my problem. I want to create a DLL (or 'something') with useful functions, which I don't want to code twice, and use those functions (and objects) both from C# and Delphi projects. The DLL I create (in C#) is usable from the C# projects I have, this is the easy part. But how do I use the DLL from within a Delphi project ? Every time I try to add the DLL to my Delphi project, Delphi rejects it. Or is there another way to do this, and store the objects/functions somehow, and use that both from C# and Delphi projects ? Thanks a lot as any help would be greatly appreciated.