In 1971, which musician appeared with T. Rex on "Top of the Pops" performing the song "Get It On"?

"Get It On" is a song by the English 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.

During a December 1971 "Top of the Pops" performance, Elton John mimed on the piano. This performance is usually the video clip for the song which has aired on various music-video outlets such as VH1 Classic.

Sir Elton Hercules John (born Reginald Kenneth Dwight; 25 March 1947) is an English singer, songwriter, pianist and composer. Collaborating with lyricist Bernie Taupin since 1967 on more than 30 albums, John has sold over 300 million records, making him one of the best-selling music artists of all time. He has more than fifty Top 40 hits in the UK Singles Chart and US 'Billboard' Hot 100, including eight number ones in the UK and nine in the US, as well as seven consecutive number-one albums in the US.