Jake Shimabukuro is still pinching himself. And Mick Fleetwood is smiling ear to ear.

That's how the two are feeling as they bring out Blues Experience, a collaborative album that finds the ukulele virtuoso and the Rock and Roll Hall of Fame drummer exploring the blues over nine tracks - one of which is a moving tribute to Fleetwood's late Fleetwood Mac bandmate, Christine McVie.

"I'm really excited about this project," Shimabukuro tells Billboard via Zoom from Hawaii, where he lives (and where he met Fleetwood, another Hawaii resident). "It's such a departure from anything I've ever done, but I love that because it really feels like I learned a lot from this experience. In my wildest dreams I never would have imagined that this album would exist someday. And I love those kinds of things...the most unlikely collaborations or combinations coming together to do something very different and unique."

Fleetwood -- who has some 40 ukuleles hanging on the walls of his home as decorations -- adds that the appeal for him was to work with someone he calls "an explorer. He's fascinated with music. He comes from a very traditional musical background, but he's done an extraordinary amount of projects with anyone from Neil Young to Bette Midler, all this strange, bizarre, super-eclectic stuff that's obviously intrigued him on his journey. That's what led to, 'What can a funny old drummer -- me -- do with someone like this?'"

Fleetwood and Shimabukuro had met a number of times over the years, establishing a friendly relationship. "We basically were passing in the night for years, always saying, 'We've got to do something together,'" recalls Fleetwood. Meeting up again at a Shimabukuro show in Maui during early 2023 put the idea on the front-burner for both, and by March they were in a studio Fleetwood has near his home, with "no pressure, no agenda, just to get in there to see what happens." Four songs in four days -- "recording everything live and just experimenting and having a lot of fun," according to Shimabukuro -- proved they were creatively in sync. Shimabukuro was even happy to plug into a vintage Fender Princeton amplifier that helped him craft a sound that "really seemed to work nicely for this genre and this style."

Playing blues was a no-brainer, even if it's something Shimabukuro had not done to a great extent before. "First, Mick's the iconic blues drummer," he explains. "I've always loved that style of music, that style of playing the guitar, that kind of phrasing. I mean, one of my all-time favorite Jimi Hendrix tunes is his version of 'Red House' when I was young. So it was in me."

Shimabukuro also acknowledges the influence on his playing of "Uncle" Joseph Kekuku, the 19th century acknowledged inventor of the steel guitar. "I'm not playing slide on my ukulele, but this album kind of brings it back to what he did and what I learned from that. It's kind of a throwback but at the same time is progressive."

Fleetwood says that his cohort "was very privy to the pedigree of early Fleetwood Mac and Peter Green. So that became sort of the template of the conversation, or at least the overview. He's very passionate about what he does, and anything with passion in it, in my quiet opinion, is connected to the blues. He's an incredibly, technically capable player, period, and he has a whole other world of looking at things in a different way, where you actually pay attention to where the blues come from. So this album ended up being a combination of his natural self, which is a huge catalog of technical ability, and what it is that I do."

Blues Experience isn't strictly blues, mind you; there are renditions of Procol Harum's "A Whiter Shade of Pale," for instance, as well as Neil Young's "Rockin' in the Free World." But the bulk of the set hews that way, including the Shimabukuro original "Kula Blues," and the Stevie Wonder-written, Jeff Beck-popularized "'Cause We've Ended as Lovers," a personal favorite of Shimabukuro's that features Sonny Landreth on slide guitar. Keyboardist Mark Johnstone from the Mick Fleetwood Blues Band plays on a couple of tracks, while bassist Jackson Waldhoff and keyboardist Michael Grande play throughout the album.

The album's most stunning moment, however, is its closing, a rendering of Christine McVie's Fleetwood Mac signature song "Songbird" followed by a spoken word coda by Fleetwood, mourning McVie's death on Nov. 30, 2022. It's a three-hanky musical elegy, even though Fleetwood says "that wasn't the intention."

"'Songbird' came out of the blue, and we couldn't not include it," Fleetwood says. "It was around the time when Christine had passed, and we found ourselves doing that song, which was not predetermined. To me that was very poignant. I was very pregnant with the loss of Christine, and the fact that we were singing it but not singing it reminded me of Peter Green; he had a great natural voice, but he also sang through his instrument. It was very emotional and also in those moments was a prayer, for sure. Christine was a huge loss for me and for millions and millions of people."

Saluting McVie on a blues album was also appropriate, Fleetwood adds. "She was a blues player," he says. "She came up through the ranks, playing with Freddie King. And she was an extraordinarily passionate songwriter; just when you thought she was on a journey into the pop world she'll go out and lay something on you like 'Songbird' that really is a lament...which is of course connective to the blues.

"Before we lost Christine there were some intentions that Fleetwood Mac would've found a way to say goodbye...but we didn't. It was unthinkable for (the band) to do any more. Stevie (Nicks) has been able to do that in many ways on the big excursion that she's doing; she's been able to do what Fleetwood Mac was not. All of that was like a sort of tsunami of feeling as we did that song. But it was also very healing, and a kind of closure."

Fleetwood and Shimabukuro played some of the Blues Experience songs live at We Are Friends -- A Maui Wildfire Benefit Concert on the island last year, and they both voice a desire to perform together again. They're also up to collaborate more, though Shimabukuro claims that "I would never want to get greedy and ask for another project like this from him -- but if he brought it up and said, 'Man, let's do another one,' are you kidding me? Oh my goodness, that would be a dream come true, like winning the lottery twice."

The odds are better than that, however. "If Jake knocked on the door and said, 'I'm actually not on the road,' I would always be open to doing something," Fleetwood affirms. In the meantime, he's working on an album of his own, collaborating with an "interesting" corps of other artists (he mentions Girl In Red specifically) and even employing some of those ukuleles from the wall.

"It's petrifying," Fleetwood acknowledges, "but it's actually turning out to be really interesting. I'm having a lot of fun doing that, and my heart is saying 'you need to do more.' Doing this (album) with Jake did me a lot of good. It was really the trigger of 'you can do this.' It's very therapeutic, and I've actually learned to express myself in little areas I never knew was there, and to whatever avail doesn't really matter. It's just about doing it, and then we'll see what it leads to."