Metallica photographed backstage at Mickey's in Milwaukee, Wisconsin, on August 14, 1983.

Metallica onstage in 1984.

James Hetfield, Kirk Hammett, Lars Ulrich and Cliff Burton backstage during the Breaking Sound Festival in Paris on August 29, 1984.

Cliff Burton, Lars Ulrich, Kirk Hammett, James Hetfield of Metallica backstage at Monsters of Rock at Donington Park, Leicestershire on August 17, 1985.

Cliff Burton, Kirk Hammett, Lars Ulrich and James Hetfield of Metallica photographed in Chicago on April 5, 1986.

James Hetfield, Jason Newsted, Lars Ulrich and Kirk Hammett in 1988.

Metallica backstage in Germany, 1989.

Metallica performing live in Irvine, California on the Damaged Justice Tour on September 22, 1989.

Metallica photographed in the early 1990s.

Jason Newsted, Kirk Hammett, Lars Ulrich and James Hetfield hold their American Music Award on January 25, 1993 in Los Angeles.

Metallica onstage in the late 1990s.

Metallica photographed in California on November 10, 1999.

Lars Ulrich testifies before the U.S. Senate Judiciary Committee on music and the Internet on July 11, 2000 in Washington, DC.

Lars Ulrich at the MTV Movie Awards at Sony Pictures Studio in Culver City, California, on June 3, 2000.

Metallica with one of their two My VH1 Music Awards at the Shrine Auditorium in Los Angeles on November 30, 2000.

Metallica rehearse before the MTV Icon: Metallica tribute special held at the Universal Amphitheatre on May 3, 2003 in Universal City, California.

James Hetfield onstage in Dublin on August 20, 2003.

Metallica at the 31st Annual American Music Awards on November 16, 2003 in Los Angeles.

Metallica onstage during the 31st Annual American Music Awards on November 16, 2003 in Los Angeles.

Metallica perform at the MTV Icon: Metallica tribute special on May 3, 2003 in Universal City, California.

Metallica at the 21st Annual ASCAP Pop Music Awards on May 18, 2004 in Beverly Hills, California.

Metallica perform during the Download Festival on June 6, 2004 in Leicestershire, England.

Metallica arrive at the premiere of Metallica: Some Kind of Monster in New York on July 7, 2004.

James Hetfield performs at the Darwin Awards Party during the 2006 Sundance Film Festival on January 25, 2006 in Park City, Utah.

Kirk Hammett performs in Imola, Italy on June 17, 2006.

Lars Ulrich, Kirk Hammett, Robert Trujillo and James Hetfield at the 21st Annual Rock and Roll Hall of Fame induction ceremony at New York's Waldorf Astoria on March 13, 2006.

Metallica perform in Stockholm, Sweden, on July 12, 2007.

Metallica onstage at a concert in Berlin to launch Death Magnetic on September 12, 2008.

Metallica pose at the O2 World Arena in Berlin on September 12, 2008.

Metallica onstage at the 2008 Bonnaroo Music and Arts Festival on June 13, 2008 in Manchester, Tennessee.

Lars Ulrich and James Hetfield at the 2008 Bonnaroo Music Festival in Manchester, Tennessee, on June 13, 2008.

Lars Ulrich at the Silverlake Conservatory of Music Benefit concert in Los Angeles on May 14, 2008.

Metallica perform at the Silverlake Conservatory of Music Benefit concert in Los Angeles on May 14, 2008.

Metallica perform at the KROQ Weenie Roast at the Verizon Wireless Amphitheater on May 17, 2008 in Irvine, California.

Kirk Hammett at the KROQ Weenie Roast on May 17, 2008 in Irvine, California.

Kirk Hammett of Metallica performs live in concert at the Oracle Arena on December 20, 2008 in Oakland, California.

Lars Ulrich of Metallica performs live in concert at the Oracle Arena on December 20, 2008 in Oakland, California.

Lars Ulrich of Metallica performs live in concert at the Oracle Arena on December 20, 2008 in Oakland, California.

Metallica perform on October 16, 2008 in Guadalajara, Mexico.