The band became arguably the biggest act in rock in the late 1970s after guitarist/singer Lindsey Buckingham and singer Stevie Nicks joined three previous members of Fleetwood Mac — drummer Mick Fleetwood, bassist John McVie and keyboardist/singer Christine McVie (the bassist’s former wife) — in 1975 and released three straight blockbuster albums, Fleetwood Mac (1975), Rumours (1977) and Tusk (1979) that established the lineup as the classic edition of Fleetwood Mac.

In a conversation with Fleetwood, it’s very clear that today’s four core band members (Christine McVie retired in 1998) are very much invested in the band and far from complacent about its live show. In fact, the band spent six full weeks rehearsing for this year’s tour, it’s first in three years.

“We know the nuts and bolts are all in place and we have confidence in that,” Fleetwood says. “But we also have like a garage band-like mentality where we go sh–, we’re actually playing down at the local town hall next week. We better be good. And it [that nervousness] doesn’t really go away, which is a nice thing. We’re not all jaded and so showbizzed out that we’re all super slick and go ‘Ah, piece of cake.’ We’re not like that at all. We’re all quite sh—ing ourselves.”

Fleetwood says the shows will, of course, feature signature hits.

“We know that we have sort of a body of songs that, in truth, if we didn’t do them, we’d probably be all lined up and shot,” he says. “So we have sort of eight or nine songs that no matter what, we know people are going to want for us to do them, and we are totally cool with doing them. If we walked on the stage and didn’t play ‘Dreams,’ I think people would be shocked. So we don’t go there. So what we do is we take the prime songs, ‘Go Your Own Way,’ ‘Dreams,’ songs like that, and then build a new show around the fact that we, of course, are going to be doing those songs.”

This is Fleetwood Mac’s first tour since 2009’s “Unleashed” tour. Buckingham and Nicks are busy with solo careers, making Fleetwood Mac part of the picture, but not the entire one. Following the “Unleashed” tour, Buckingham released the studio album, Seeds We Sow, and Nicks released In Your Dreams. Both artists toured extensively to support the albums.

The personal history and inter-personal dynamics within Fleetwood Mac also create challenges, and, according to Fleetwood, are another indication of why the four band members are all in when they reunite.

“When we do do it, we work really hard at it and we’re committed to it,” he says. “We fundamentally have to be happy to be doing this because we’re all ex-lovers and all the stuff that is well worn news out there.”

As has been well documented, Buckingham and Nicks were a couple (and were recording as Buckingham-Nicks) when they joined Fleetwood Mac. The McVies were also married at that time. But the relationships soon frayed, and the Rumours album (a deluxe expanded edition of the CD was released in January) was written in the midst of those breakups. Fleetwood and Nicks later became a couple for a time, while Buckingham later married and started a family.

“[This is] a bunch of people who aren’t just connected by the music, but connected by spending huge amounts of time [together], including Lindsey, Stevie and their journey,” Fleetwood says. “No, they’re not in love and Lindsey has an incredibly wonderful family. But the story they tell as two people is huge. And you know, there I am with Stevie, and me and Stevie had a long-lasting love affair. She’s the godmother of my children and it’s a trip. It’s a trip.”

This year’s reunion could turn out to be even more eventful than the one in 2009.

On the “Unleashed” tour, Fleetwood Mac essentially played a greatest hits set. But Fleetwood says this tour will blend in three or four new songs from those recorded last year when Buckingham, Fleetwood and McVie got together for a writing and rehearsal session.

“Stevie was on the road, and during that period she lost her mother, who passed,” Fleetwood says. “So she was not set up to come and join the party in that few weeks that me and Lindsey and John put some ideas together that Lindsey had.”

Nicks has since added her vocals to several of the songs Buckingham, Fleetwood and McVie recorded during the sessions and three of those songs will be available through iTunes shortly. Another song was written by Nicks. It’s an unreleased tune that dates back to before Nicks and Buckingham joined Fleetwood Mac, and was recently rediscovered by Nicks and recorded with the band.

“It really tells the story of how Stevie and Lindsey joined Fleetwood Mac, which is when they were known as Buckingham-Nicks,” Fleetwood says. “It was an unrecorded song that Stevie actually wrote about Lindsey, and it’s a beautiful song …

“And this was the music that I heard in the studio that spurred me on to make the phone call and ask them to join Fleetwood Mac.”

Fleetwood says with any luck these songs will form the basis of a new Fleetwood Mac album that may be recorded later this year and released either ahead of Christmas or in early 2014.

This would be Fleetwood Mac’s first collection of new music since 2003’s Say You Will. That was the band’s first album without Christine McVie, and the tour that followed the album was not as harmonious as the band members would have wanted.

For Nicks, it was difficult to be the only woman in the band and she sorely missed her close friend, McVie. And before regrouping for the “Unleashed” tour, the band flirted with having Sheryl Crow (a good friend with Nicks) join the band.

Nicks, in various interviews, has said she now is comfortable in the four-person Fleetwood Mac lineup, and Fleetwood notes that the guys try to help create a good environment for Nicks.

“Certainly the guys in the band are very aware of making sure that Stevie feels safe,” Fleetwood says. “When she comes back to Fleetwood Mac, she’s in a man’s world, you know. And two of them are men that she each had relationships with. It’s hugely important that she feels safe — and loved. And that’s the funny old thing that this band is all about. It’s powerful.”

FLEETWOOD MAC

• When: 8 p.m. April 6
• Where: Wells Fargo Center, Broad Street, Philadelphia
• How much: $49.50, $79.50, $149.50
• Set list: Hits such as “Go You Own Way” and “Dreams,” and recently recorded new music
• Info: comcasttix.com

Alan Sculley / The Morning Call / Thursday, April 4, 2013