Least of all Tommy. But right now, our...inventive four year old is pulling up his red pajama shorts really high, sticking his arms through the leg holes, turning it into a loincloth with sleeves.
Pretty much this, yes.
Anyway, here's the Internet Movie Database entry for the 1974 John Boorman film, which somehow did not get an Oscar for Best Costume Design.
[Update: Commenter Xena Catolica alerts us to the fact that the B-Movie Catechism site did a review of Zardoz. Well worth a read.]