“Get It On” is a song by the British glam rock group T. Rex, featured on their 1971 album Electric Warrior. Written by frontman Marc Bolan, “Get It On” was the second chart-topper for T. Rex on the UK Singles Chart. In the United States, it was retitled “Bang a Gong (Get It On)” to avoid confusion with a song of the same name by the group Chase.
Bolan claimed to have written the song out of his desire to record Chuck Berry’s “Little Queenie”, and said that the riff is taken from the Berry tune. In fact, a line (And meanwhile, I’m still thinking) of “Little Queenie” is said at the fade of “Get It On”.
This was the song that virtually ended the once-solid friendship between Bolan and John Peel, after Peel made clear his lack of enthusiasm for it on air after playing his advance white label copy. Bolan and Peel only spoke once more before the former’s death in 1977.
During a December 1971 Top of the Pops performance, Elton John mimed a piano on the song. This performance is usually the video clip for the song which has aired on various music-video outlets such as VH1 Classic.
The track was recorded at Trident Studios, London and the piano on the record was performed by either Rick Wakeman or Blue Weaver. Mark Paytress notes that both pianists may have played separate parts on the song, with Wakeman contributing only the piano glissandos that feature several times throughout the song. 
Saxophones were played by Ian McDonald of King Crimson. Producer Visconti later recalled: “He played all the saxes, one baritone and two altos. I kept the baritone separate but bounced the altos to one track. I bounced the backup vocals to two tracks, making an interesting stereo image.” Mark Volman and Howard Kaylan provided back up vocals.
Marc Bolan: lead vocals, guitar
Rick Wakeman: electric piano and Hammond organ
Ian McDonald: baritone and alto saxophone
Steve Currie: bass guitar
Bill Legend: drums
Mark Volman and Howard Kaylan: backing vocals
It spent four weeks at the top in the UK, starting 24 July 1971 (“Hot Love” was number one for six weeks from March to May), and it was the group’s biggest hit overall, selling nearly a million copies in the UK. It peaked on the US Billboard Hot 100 chart at number ten and at #12 in the Cash Box Top 100 in March 1972, becoming the band’s only major US hit. The song reached No. 12 in Canada in March 1972.