Give a stream of consciousness and then the final answer. "Let's Call the Whole Thing Off" is a song written by George Gershwin and Ira Gershwin for the 1937 film Shall We Dance, where it was introduced by Fred Astaire and Ginger Rogers as part of a celebrated dance duet on roller skates. The song is most famous for its "You like to-may-toes / tmetoz / and I like to-mah-toes / tmtoz /" and other verses comparing their different regional dialects.

Answer this question: who wrote the song let's call the whole thing off?
This is the relevant information: "Let's Call the Whole Thing Off" is a song written by George Gershwin and Ira Gershwin for the 1937 film Shall We Dance, where it was introduced by Fred Astaire and Ginger Rogers as part of a celebrated dance duet on roller skates.
So, the final answer is George Gershwin and Ira Gershwin.