"20th Century Boy" is a song by T. Rex, written by Marc Bolan. It was released as a single in 1973 and reached No. 3 in the UK Singles Chart. The song did not feature on an original studio album but was included as a bonus track on a reissue of 1973 album Tanx.
It later returned to the UK Top 20 in 1991, peaking at No. 13, fourteen years after Bolan's death, when it was used in a Chris Hartwill-directed commercial for Levi's starring Brad Pitt. A slightly different segment of the song, with the addition of a harp, was used in a Jameson Irish Whiskey television advertisement. It plays a key role on the science fiction-mysterymanga20th Century Boys.
The English hard rock band Def Leppard covered the song on their 2006 album, Yeah!, which features cover versions of 1970s rock hits. It was released as the third and final single from the album, on 21 August 2006. The band used the song extensively as promotion for including two tv appearances and a regular rotation in the setlist of their 2006 Yeah! Tour. Def Leppard performed "20th Century Boy" on The Tonight Show with Jay Leno on 23 May 2006 two days before performing the song with Queen's Brian May on VH1 Rock Honors broadcast on 31 May.
^Brackett, Nathan; Hoard, Christian (2004). The New Rolling Stone Album Guide (4th ed.). Simon & Schuster. p. 822. ISBN978-0-7432-0169-8. Bolan (...) started writing manic chant-along glam-rock hits such as "Metal Guru," "20th Century Boy," "Solid Gold Easy Action," and "Children of the Revolution."