You might not expect a comedy routine during a conversation with Robert Plant and Alison Krauss.

But the rock 'n' roll lion and the bluegrass chanteuse who became an unlikely musical pair 17 years ago with their rootsy collaboration “Raising Sand” are relaxed, playful and exceptionally respectful of each other.

And very funny.

In a joint interview a few days before the June 2 launch of another summer of touring behind “Raise the Roof,” their 2021 acclaimed follow-up to the Grammy-winning “Raising Sand,” the pair begin by disagreeing about when their last tour ended (it was July) and tease each other while answering how they might change the setlist for this run of dates.

“We haven’t started yet, but we have 39 shows so I think we’ll consolidate and play to our strengths initially,” Plant says.

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“And then we’ll play to our weaknesses,” Krauss jokes.

“See what I’m dealing with?” Plant responds with mock exasperation.

For 25 minutes, the pair banter about aging (he is 75, she 52), why sleep is “crucial” while touring and the art of harmonizing.

“I’m trying my best to learn how to get it right,” Plant, one of the mightiest singers in rock history, says with discernable humbleness.

Here is what else the twosome had to share.

Question: What have you both been doing since getting off the road last year?

Robert Plant: I’ve been very busy following my north star and reaching into the great old world of R&B for songs I might do something with down the road. And watching football (soccer).

Alison Krauss: I’ve been watching documentaries about The Mothman. And have been in the studio with Union Station working on a new album.

What is it like making the shift from touring with Robert to going back into the studio?

Krauss: It’s much more laid back with Robert. The studio has its own unpleasantness, and it’s a much more relaxed environment here. I can’t believe I get to do both.

Plant: You have a lot more notes to worry about in that band. I’ve learned a lot in my time around Alison and the world that comes with her and it’s been a spectacle of charm, politeness and peach cobblers.

You mean, Southern?

Plant: Yes! You do a studio session in Nashville and you have to make your way through the baked goods. In England it’s much more rough and ready. The people in Nashville, there is a standard and quality and texture there.

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You’ve had these songs out on the road the past couple of summers. What has changed in either the setlist or your approach to the music?

Krauss: All of these songs, they turn into something else the longer you live with them, like I wish we would have recorded it this way or phrased it like that. When you sing the same song (live), the stories change.

Is your rapport deep enough now that you can look at each other onstage and know the song is going somewhere?

Krauss: I know when he looks at me he’s going somewhere, but I don’t know where.

Plant: I never sang harmony in Led Zeppelin except for “Thank You.” I really didn’t know about singing with another person. I do believe that Henry “The Horse” (Smith), our guitar roadie, and Jimmy (Page) sang the harmonies with me on that one. But I loved listening to what Alison sang.

Robert, do you think if you hadn’t connected with Alison a couple of decades ago, that you would have stayed in music?

Plant:  I’ve been really fortunate because it was such a formative time in my life when Led Zeppelin came to a screeching halt and I had to keep moving and find a new place to do what I do and challenge myself … This woman sitting next to me is manna from heaven.

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You’re also going on tour with Bob Dylan and Willie Nelson. Are you technically the opening act?

Plant: I think they’re doing ice cream sundaes and hot dogs when we play. But I do think there is one person on before us. Regardless, I’m proud to be standing next to Alison before the master (Dylan) takes the stage.

Alison, tell me about your friendship with Def Leppard since you sang on a couple of songs on their "Diamond Star Halos" album.

Krauss: All of the bluegrass-ers love Def Leppard. Their harmonies, the way they would blend. It was so incredible to do those songs. They were so generous and nice.

Plant: So different than Robert (laughs).

Krauss: Right, not like Robert. I said they were so generous and nice (laughs). It was a fantasy. There are plenty of people who grew up playing the kind of music I did and fantasized about playing a (rock) part.

There are always a few reconstructed Led Zeppelin songs in your show. Robert, do you enjoy doing them or is it more obligatory?

Plant:  I love them and am very proud of them and to get to change them around and to hear that voice next to me, it allows for an exotic overview of the more dramatic elements. At times I’m emotional about it because I’m hearing these songs – they are all beautiful adaptations that I could never have dreamt. It’s a great achievement.

Since it’s been almost a year since you last toured, do you have to do anything health-wise to get ready?

Krauss: Just sleep.

Plant: Sleep is crucial. Having jet lag, that’s a crippler. You’ll be awake at 4 a.m. sending notes to people, thinking should I read a book for awhile? No, go to sleep!

Have you discussed any future recordings together so it won’t be another 14 years between albums?

Plant: Time is a funny thing, isn’t it? Alison is going back on the bluegrass trail, so I guess if she wants me back, she can give me a call.