It was one of the most unusual collaborations since Bowie and Bing – right up there with Elton and Eminem, and Meatloaf and Cher – but Robert Plant and Alison Krauss scored not only a massive hit, but five Grammy awards with their 2007 album “Raising Sand.”

Now the duo – Plant the legendary former Led Zeppelin frontman (still going strong at 71), and bluegrass siren Krauss from Union Station – are back for another go with “Raise the Roof,” reprising their successful original formula of understated roots rock (blues, folk, country) delivered with effortless and unerring vocal harmonies that coalesce into fresh mainstream appeal that is mature and enduring.

Undoubtedly once again bound for Grammy glory, the album debuted in the top 10 on several of Billboard’s charts late last year, built in part on the success of its first single, a cover of Lucinda Williams’ “Can’t Let Go,” from her great (and Grammy-winning) 1998 album “Car Wheels on a Gravel Road.”

Lyrics

Told you, baby, one more time
Don’t make me sit all alone and cry
Well, it’s over, I know it but I can’t let go

I’m like a fish out of water, a cat in a tree
You don’t even want to talk to me
Well, it’s over, I know it but I can’t let go

He won’t take me back when I come around
Says he’s sorry then he pulls me out
I got a big chain around my neck
And I’m broken down like a train wreck
Well, it’s over, I know it but I can’t let go

See I got a candle and it burns so bright
In my window every night
Well, it’s over, I know it but I can’t let go

You don’t like to see me standing around
Feel like I been shot and didn’t fall down
Well, it’s over, I know it but I can’t let go

He won’t take me back when I come around
Says he’s sorry then he pulls me out
I got a big chain around my neck
And I’m broken down like a train wreck
Well, it’s over, I know it but I can’t let go

Turn off the trouble like you turn off a light
Went off and left me, it just ain’t right
Well, it’s over I know it but I can’t let go

Around every corner, something I see
Brings me right back how it used to be
Well, it’s over, I know it but I can’t let go

He won’t take me back when I come around
Says he’s sorry then he pulls me out
I got a big chain around my neck
And I’m broken down like a train wreck
Well, it’s over, I know it but I can’t let go

He won’t take me back when I come around
Says he’s sorry then he pulls me out

I got a big chain around my neck
And I’m broken down like a train wreck
Well, it’s over, I know it but I can’t let go

It’s over, I know it but I can’t let go
It’s over, I know it but I can’t let go
It’s over, I know it but I can’t let go