One of the earliest jam sessions by one of heavy metal's most consequential lineups was recorded to video tape at the time and can now be viewed online.

Megadeth's 1990 Rust In Peace album is one of the most important thrash metal records of all-time and, by extension, the four musicians who recorded the album are one of the genre's most influential combos.

Archival video, taken from Megadeth's 2006 anthology release, shows the band's '90s lineup (its longest serving foursome) rehearsing the Peace Sells...But Who's Buying classic "Wake Up Dead," not long before going into the studio to record their magnum opus.

While frontman Dave Mustaine and bassist Dave Ellefson have been fixtures in Megadeth from the start, 1989 brought a shake-up in the band with the hiring of drummer Nick Menza and lead guitarist Marty Friedman.

Friedman, the last piece of the puzzle, was hired on the spot after the jaded band had endured dozens of failed try-outs by every manner of '80s scene-creature stereotype you could imagine.

The former Cacophony shredder Friedman was borderline homeless when he arrived at the Megadeth audition carrying a cheap guitar with no case.

But Friedman's disheveled appearance belied his unreal command of his instrument. Mustaine recalls in the band's Rust In Peace: The Inside Story of the Megadeth Masterpiece memoir that Friedman's chops were so otherworldly, they made him doubt his own prowess on the instrument.

The rehearsal tape begins with someone off-camera announcing that Friedman had "successfully passed the audition," and all parties involved were "ready to institute the next Megadeth lineup."

One of the first things Megadeth asked of Friedman after he joined the band was for him to fix his hair, which was half-bleached and half its natural color. But the video above was taken so soon after his audition, he's still sporting the bizarre hairdo while running through "Wake Up Dead."

The Rust In Peace lineup recorded four albums together — including the acclaimed Countdown to Extinction (1992) and Youthanasia (1994) — remaining in tact until Menza's departure in 1998. Friedman left the group two years later.

While the band discussed a 25th anniversary reunion in 2015, the members weren't able to agree on terms. Menza passed away of heart failure in 2016.

Photo: Getty Images