According to Actors' Equity, Gentlemen Prefer Blondes chorus member Bill Bradley sent a robe of fellow chorus member, Florence Baum, to another friend for the opening night of Call Me Madam. Claiming that it had been worn by all of Ziegfeld's girls from the Follies shows, the robe was supposed to bless the show's beginning of its run. Later, a decorative element from one of Ethel Merman's gowns was added, cementing the moniker of the "Gypsy" robe, and beginning the tradition of the cast adding decorations and signing the robe.
For 60 years, the Broadway community has practiced the tradition of presenting the "gypsy robe" on opening night to that production's chorus member with the most Broadway chorus contracts.
See also: Gypsy of the Year, gypsy, gypsy life