Robert Plant and Alison Krauss on Why They Never Dated: 'We'd Be in Trouble Now'

Robert Plant and Alison Krauss' chemistry is off the charts — at least, when it comes to their music.

The pair caught lightning in a bottle when they joined forces on the Grammy-winning 2007 album Raising Sand, and are looking to do so again with Raise the Roof, a new collaboration out Nov. 19.

And although the Led Zeppelin rocker, 73, and the bluegrass darling, 50, share a close friendship, that bond — and considerable critical success — doesn't exactly translate into their personal lives.

The pair were quizzed in this week's issue of PEOPLE on whether they were aware of internet chatter that perhaps their friendship was something romantic — chatter they quickly shut down.

"I haven't heard it in a long time, but we did. We still do," Krauss says of having a relationship with Plant.

"But not that one," Plant interjects, before Krauss chimes in to clarify: "We have a musical one."

Ever ready with a wisecrack, Plant quips: "Because if we had that one, we'd be in trouble now. Trouble, party of one."

With the coast clear of trouble, the two are ready to make a new mark with Raise the Roof, which features 12 new tracks, all covers just like last time, save for "High and Lonesome," an original that Plant wrote with producer T Bone Burnett.

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A return to the studio 14 years later was easy for Plant, who says he and Krauss are "good together."

"We're just good," he says. "I think we are determined and gritty. We like the idea of seeing things straight down the line, no fluffy stuff. So if we don't get it right, we have to move on. And we're friends, really good friends, so we can reach a 'no' really quickly if it's not feeling right.

Krauss, meanwhile, says she and the British rocker share a "real love for history and where we both come from."

Though they bonded over such similarities, there was a learning curve, at least in the beginning, as Krauss essentially tutored Plant during their first go-round, especially when it came to harmonies.

"We've got our own individual strengths, and it's a miracle that they can ever meld. But they do," he says. "In the beginning it was difficult, because I wasn't used to being tutored and, 'Why don't you do it like this?' And I just thought, 'Oh, baby!'"

Still, he says, "I like it. I like the idea of learning new stuff… I felt so much more accomplished when it started to work good."

Looking ahead, Krauss and Plant hope to one day take the record on tour, once COVID-related logistics ease — and aren't closing the door on a third album.

"I don't see any reason why not. There's a world full of beautiful songs that are waiting to be brought back into focus in a different way," says Plant. "I can't see any reason that that shouldn't work."

For more from Robert Plant and Alison Krauss, pick up the latest issue of PEOPLE, on newsstands everywhere Friday.