After 41 years with Tom Petty and the Heartbreakers and two years with Fleetwood Mac, guitarist Mike Campbell is finally gaining confidence as a songwriter and singer with his own band, the Dirty Knobs.

That's evident on the new "Vagabonds, Virgins & Misfits," the Knobs' third album in four years.

"It's taken me a while to get to the confidence as a writer with words and vocals. The confidence is 90 percent of the game," said Campbell, whose band will perform Friday at the Fitzgerald Theater in St. Paul. "If you believe I can make this happen, then it starts to happen. I'm a late bloomer, I guess."

Years ago, when Petty would select maybe two out of 20 music tracks Campbell composed, the guitarist started experimenting by singing his own lyrics in his home studio, figuring no one would hear them.

"It was pretty bad I must admit because I was afraid nobody would like the sound of my voice," Campbell said last week. "Slowly I got a little more comfortable with it and I found a way to get the song across without being Roy Orbison. Nobody can sing like that. But I can get personality into the songs and I'm getting better with the pitch. The confidence comes from repetitive working. It just kind of snowballed."

Campbell had enough confidence in his singing and songwriting to resurrect five songs from the vault at his wife's suggestion for "Vagabonds."

He had enough confidence to invite Graham Nash to sing on a track, the inspiring ballad "Dare to Dream," when the latter was being interviewed by Campbell on Tom Petty Radio on SiriusXM.

"I begged him. He said, 'Sure I'll make your song better.' Tongue in cheek," Campbell recalled. "So I sent him the song, me being a Hollies groupie, and I was thrilled when he sent it back to me with layered voices like a Hollies record."

Campbell reached out to Lucinda Williams at the end of their interview on SiriusXm. She joined him for the twangy, Dylan-esque "Hell or High Water," adding a verse in her distinctively delectable drawl.

"The song was finished. It's not a pop song but it's a story; there's a character who comes in contact with a female character," Campbell explained. "I said what would make this better is if a female was actually singing those words. And she made the song 10 times better."

Chris Stapleton, who guested on the Knobs' previous album, "External Combustion," joined this time on the boogieing "Don't Wait Up," along with Heartbreakers keyboardist Benmont Tench.

Campbell's confidence carries over to the stage as a frontman, especially now that he has the safety net of a teleprompter.

"Being a frontman and leading the band and engaging the audience and remembering the lyrics, it's a whole lot more work. Telling the band when to get loud and when to get quiet, remembering all the guitar parts, singing the harmonies," he rattled off. "It's a whole new world and I'm really loving it."

The Knobs, who started in 2004 but didn't become full time until four years ago, have a revamped lineup for the new album and tour, with Chris Holt on guitar and Steve Ferrone on drums.

Ferrone, who played with the Heartbreakers for their final 23 years, was the original Knobs drummer but Matt Laug took over before recently exiting for his dream gig with AC/DC. Two years ago, the Texas guitarist/keyboardist Holt signed on.

Dirty Knobs concerts usually feature three songs from the Tom Petty & Heartbreakers catalog, chosen at soundcheck. Campbell said the fans like to hear them, but he wants the Knobs to have their own identity.

When it comes to running the band, Campbell follows Petty's lead.

"I'm not a dictator. I want to be a member of a group where we all have an opinion. I'm not always right. I learn from them. I surround myself with people I respect. It's a democracy, but whoever is singing the song usually has the last word."

Lessons from Bob Dylan

Campbell, 74, grew up in Jacksonville, Fla., though he didn't know the members of Lynyrd Skynyrd, who were reared there at the same time. They did share some bills early in their careers. In 1971, Campbell got recruited into Petty's Mudcrutch, which evolved into the Heartbreakers in 1976.

In 1986, Tom Petty and the Heartbreakers got hired as the Bob Dylan backup band for an entire tour.

"It was life-changing. You're inspired," Campbell recalled. "He has such a sharp wit. He's so intelligent and well read. It was very spontaneous and brought spontaneity back to our own gigs. Think on your feet, play without fear. He taught us to do that again. It made us more loose. And Tom got to be another dude in the band instead of leader."

Campbell got to back Dylan again last year at Farm Aid.

"It was under-rehearsed, kind of crazy and cool," the guitarist said. "It was the first time I'd played with Benmont in a while. It was kind of spiritual."

This year, Campbell backed up Margo Price on "Ways to Be Wicked" for a just-released "Petty Country," featuring Dolly Parton, Luke Combs, George Strait, Lainey Wilson and others interpreting the tunes of Petty. The song was suggested by the album's producer, George Drakoulias, who worked with Petty and the Dirty Knobs.

"The song holds up," said Campbell, noting Lone Justice recorded the song before Petty did. "It's snide, snarling Petty."

While Campbell is known for his guitar work, he's pictured on the cover of "Vagabonds, Virgins & Misfits" holding a dulcimer. In the liner notes, he thanks Stevie Nicks for "the cool" folk instrument.

The reason is that one day at a Fleetwood Mac session, Mick Fleetwood showed up with a dulcimer and Campbell expressed his admiration for it. A week later, Nicks gifted Campbell with a similar dulcimer and, to Nicks' surprise, he learned how to play it, which he does on the Byrds-evoking "Innocent Man" on the new Knobs project.

Campbell hasn't heard from Nicks about the new record, which was released in June. And he hasn't talked to anyone else in Fleetwood Mac, though he received an email from drummer Fleetwood.

Will the group — which hasn't done anything since the death of Christine McVie in 2022 — get back together?

"I don't see it," Campbell said. "I went to high school. Then I moved on. Stevie's got her own band. I've got my band. Fleetwood Mac, they've done it. They were undeniably one of the top bands."

Mike Campbell & the Dirty Knobs

Opening: Shannon McNally.

When: 8 p.m. Fri.

Where: Fitzgerald Theater, 10 E. Exchange St., St. Paul.

Tickets: $52.50 and up, axs.com