Sorry about the widescreen mode - I can't alter it - anyway here is Fred and Ginger dancing what I think is their masterpiece - i would also have just tipped Irving ...
From "Follow the Fleet" (1936)
Performer: « Fred Astaire » « Let's Face the Music and Dance » Audio : Very Hq - CD Quality Sound -- MP3 320 Kbps Album : « Fred Astaire.
Fred Astaire & Ginger Rogers - Let's Face the Music and Dance (Follow the Fleet 1936) [Restored]
Ginger Rogers & Fred Astaire http://www.imdb.com/title/tt0027630/