Queen of Country with the King of Beer

At the end of the show Melissa came back out carrying a bottle (Molson Canadian) and a can of beer (Budwieser) as a part of the act when she handed the can to Reba then said "Looking at this - The Queen of Country with the King of Beer". I think this was not planned as everyone on stage broke out in laughter as if they had not heard that one before. You can see from Kelly's and the band members behind them that they loved the line. Reba even had a hard time keeping a straight face