Should I have a potential JV partner sign before an offer?

I've come across a deal in which I need a JV partner with more experience. I found someone interested in doing the deal with me and we're going there to get it under contract today. He will be cutting a check with the offer. Should I have my potential JV partner sign a JV or any other sort of agreement prior to us making the deal with seller. It's a pretty big deal and I just want to protect myself. Thanks in advance.