One report Clients and leads together

One report Clients and leads together

Hello,

I hope any one can help me. We are normaly working with leads, but recently also with clients. I have a field that says 'newsletter yes/no'. 
I want to make a report from both leads and clients to get e-mail addresses from them. I can't find where to put them together in one report. 
Hope somebody can help me.

Greetings
Karin