Surely Bolan appeared on TOTP singing "Get It IOn" in 1971, not 1972! The single was a hit in July 1971, getting to number 1 in August of that year. Elton John guested on piano and the video can still be seen on YouTube.

Yes, Steven is quite correct: "Get It On" was a number one hit in the UK in the July and August of 1971 (NOT '72).
For a period of about 18 months - commencing in the spring of 1971 and ending in the autumn of '72, or thereabouts - Bolan was a ginormous star. In fact, he was probably the most famous man in England at that time - apart from George Best (the brilliant and flamboyant Manchester United footballer), Ted Heath (the Prime Minister of the day) and Prince Charles.

I think I am correct in saying that Mr Rick Wakeman played keyboards on the original version of "Get It On" - i.e the version which was released as a single in the UK.