For the biggest part of 2003, the band is touring around the world. Apart from shows in the US, Canada, Japan and the UK, the "X" tour also takes the band to places they haven't been to in a long time (such as Germany and Poland) -- or even never before (such as Latvia, Lithouania and Russia). After 151 shows, the "X" tour comes to an end in Moscow.
Most of the year is spent on recording a new album, consisting of cover versions of the band's favorite songs from their youth. By the end of the year, an updated version of the 1995 Greatest Hits release "VAULT" is released on CD and DVD: "BEST OF DEF LEPPARD" (North Americans will have to wait a little longer, as their release for this album will be available a couple of months later). The album contains one 'new' song; "WATERLOO SUNSET", originally recorded by The Kinks, is a preview of the upcoming covers album.
In May, the North American version of the updated Greatest Hits compilation is released: "ROCK OF AGES - THE DEFINITE COLLECTION" has new artwork, a slightly different tracklisting and, instead of "WATERLOO SUNSET", another preview of the covers album: Def Leppard's version of Badfinger's "NO MATTER WHAT". In June, a co-headline tour with Bryan Adams kicks off in the USA and on July 2, Def Leppard is part of the LIVE 8 festival in Philadelphia, where they play in front of 1,000,000 people.