We all know the answer to that.
Heidi Klum donned a Native American-inspired feathered headdress (atop a sheer vest and tight trouser combo) at Unicef's Playlist with the A-list event which sees celebrities take to the stage for a selection of musical performances. Translation: famous people karaoke night!
We're going to assume from the picture below that at least one of the musical numbers was that Village People classic, YMCA. And that the choreographer had gone for a toilet break given the quartet only managed to spell A, C, M, A.
WHERE'S THE 'Y'?!
Oh - there it is (ish):