James Cagney and Joan Leslie
Yankee Doodle Dandy, Michael Curtiz, 1942, Warner Bros.
http://en.wikipedia.org/wiki/Yankee_Doodle_Dandy
"Mary's a Grand Old Name" (1906)
from the Broadway show "Forty-Five Minutes from Broadway"
Written by George M. Cohan
Sung by James Cagney and Joan Leslie (dubbed by Sally Sweetland)