Talking to Paul Morley on Christmas Eve, Bruce Forsyth said he could tell a good dancer from the way they walked. Fred Astaire had a remarkable walk. It was like a pre-war version of the pimp roll but executed by a body that couldn't be made to do anything inelegant. It's interesting how many of Astaire's routines begin with him ambling into shot and then slowly turning a walk into a dance. It's this transition from business to pleasure in a few paces that most people find most difficult when taking to the dance floor.