Is it appropriate to say that the person I'm having a conversation with is my conversation-partner, or do I have to say conversational partner? And if "conversation-partner" is Ok, what about conversation-mate?
I will give a concrete situation: Let's say I have a radio program, and I say: "Today we are going to talk about Physics. My conversation-mate is John Doe". So in this situation, which expression is better?
Last note: This question is not a duplicate. There is no question about "converation-mate". Also, I don't want to use less common words like "interlocutor" or "conversant".