Vince Gill and Amy Grant, who performed together for two sold-out Christmas shows in Nashville's famed Ryman auditorium this week, have entirely different approaches when it comes to performing. Thankfully, their differences balance each other well when sharing the stage on their Christmas tour.

"Vince hired the band," Grant tells Nashville's Tennessean newspaper. "For me, it's all about song selection and the order of the songs. For him, it's all about who's playing which part -- it's like casting a movie. So we care intensely about the whole thing, but we sort of focus on different areas."

Gill and Grant, who first performed together in the early 90s, knew early on they approached their shows from different angles. "The day after, he would be on the golf course and I would go sit in a bathtub for an hour, until the water got cold. I was analyzing the night before: 'How did that flow into that? How did that musical journey go?' He thinks as much about a guitar solo, but I don't play a guitar solo."

Performing together is a rare treat for the couple, who both have successful solo careers that have spanned over 25 years each. Grant admits, however, that what works for one definitely wouldn't work for the other. "Vince likes to change his set list every night," she says. "I might do that, but not for something as important as this. When you really go, 'This flows into this; let's keep this and make it feel like molasses flowing through the night.'

"On other tours, he has just gone, 'Argh!' But the sameness of it for me is comforting. That is the one thing that is different for us. If it were up to him, I think he would just change the song order every night."

Gill and Grant's 15-date concert event also includes Gill's daughter, Jenny, and a 12-piece band. It wraps up tonight with another performance in Nashville.