"Singin' in the Rain" is a song with lyrics by Arthur Freed and music by Nacio Herb Brown, published in 1929.
The song is a centerpiece of the musical film of the same name, Singin' in the Rain (1952). It is unclear exactly when the song was written; it has been claimed that the song was performed as early as 1927. The song was listed as No. 3 on AFI's 100 Years...100 Songs.
The posted song sheets are similar to the Gene Kelly version BUT be sure to check out the Cliff Edwards (Ukulele Ike) original version with this verse that of course has an entirely different set of chords:
Why am I smiling why do I sing
Why does December seem sunny as spring
Why do I get up each morning to start
Happy and het up with joy in my heart
Why is each new task a trifle to do
Because I am living, a life full of you