Technically, Eddie Vedder's new album and tour are a solo project. 

But the longtime Pearl Jam frontman was anything but alone on the almost-accidental venture. “The Earthling" was all about collaboration and camaraderie.

“It’s my picture on the cover of the record but really there should be so many people on it,” Vedder said when he first played the finished album for a small group of friends and reporters at a Hollywood studio. "People just kept elevating the sounds by contributing.”

It features a band of his peers, including producer Andrew Watt, Red Hot Chili Peppers drummer Chad Smith, and former Chili Peppers guitarist Josh Klinghoffer, along with guest stars including Elton John, Stevie Wonder and Ringo Starr that made the process feel like a fantasy camp.

The album is like a tour through music history in more ways than one. Released in February, it now sits atop the Billboard album sales chart, which measures traditional in-store purchases of CDs and vinyl.

“Years ago, selling records seemed a little bit scary, then all the sudden you didn't sell records anymore,” Vedder said during the band's tour stop at the YouTube Theater in Inglewood, California. “We sold enough records of this one last week to actually be the No. 1 record. So I'm not scared anymore."

Vedder has previously undertaken projects that were more purely solo, including the 2007 soundtrack to “Into the Wild” and 2011′s “Ukulele Songs.” He said the solitude was great at first.

“I didn’t have to have any arguments with anyone else,” he said at the listening gathering. “But it turns out you just end up arguing with yourself.”

He said worthwhile music comes from “allowing yourself to listen and accept the other guy’s idea.” In this case, the other guy was Andrew Watt.

Watt, the reigning Grammy producer of the year, who has made records with John, Ed Sheeran, Cardi B and Ozzy Osbourne, co-wrote every song on “The Earthling,” produced the album, played bass and other instruments on it and plays guitar with the touring band, fittingly dubbed the Earthlings.

Vedder was in Southern California to play the "Vax Live" concert in May 2021 when he asked Watt, a self-described Pearl Jam “super-fan,” if he could stop by his studio.

As they hung out, Vedder started tinkering with Watt's instruments. Watt got interested and started joining him. The songs started flowing in quick succession.

Vedder said he knew they had to make an album as soon as it got beyond a two-song single.

“Beware the third song,” he said with a laugh.

They assembled the band and got a wish-list of guest stars.

Tom Petty and the Heartbreakers keyboardist Benmont Tench lends his Hammond organ to a pair of songs, including the album's first single, the Petty-inflected “Long Way.”

John duets with Vedder on “Picture,” a song that originated when Watt asked Vedder to write some lyrics for a John album.

“I got to be Bernie Taupin for a weekend,” Vedder said.

The 73-year-old John "was really rockin'” on the hard-driving song, Vedder said, but the 71-year-old Wonder rocked even harder, providing fiery harmonica for the punk-paced “Try."

“He didn’t even flinch when he heard the tempo," Vedder said. "It was an amazing thing to witness.”

When they were recording the Beatles-esque “Mrs. Mills,” named for an old piano at Abbey Road Studios, Watt said, “We could have Chad do it. Or we could call Ringo.”

They called Ringo. The 81-year-old agreed.

“With a little help from our friends,” Vedder said with a smile.