Two of the undisputed kings of country music finally appeared on the same stage over the weekend. This is all part of a tribute to Willie Nelson. The two sang together on "Good Hearted Woman" at Willie's all-star tribute show in Nashville. The show also featured performances by Jimmy Buffett, Alison Krauss, Kris Kristofferson and more. The show will air at a later date on A&E. What two singers would you like to see perform together?