First performed by Iréne Bordoni (1928).
First recorded by Irving Aaronson & His Commanders (1928).
Hit versions by The Paul Whiteman Orchestra (US #5 1929), Dorsey Brothers & their Orchestra (US #9 1929).
From the wiki: “‘Let’s Do It, Let’s Fall in Love’ (also known as ‘Let’s Do It (Let’s Fall in Love)’ or simply ‘Let’s Do It’) was written in 1928 by Cole Porter. It was introduced in Porter’s first Broadway success, the musical Paris (A Play with Songs) (1928), by French chanteuse Irène Bordoni for whom Porter had written the musical as a starring vehicle, and was first recorded B.A. Rolfe & His Palais D’or Orchestra. The song was later used in the English production of Wake Up and Dream (1929) and was also used as the title theme music in the 1933 Hollywood movie, Grand Slam.
“‘Let’s Do It’ was the first of Porter’s famous ‘list songs’, featuring a string of suggestive and droll comparisons and examples, preposterous pairings and double entendres, dropping famous names and events, drawing unexpectedly from highbrow and popular culture.
“One commentator saw the phrase Let’s do ‘it’ as a euphemistic reference to a proposition for a sexual intercourse. According to this argument, ‘Let’s Do It’ was a pioneer Pop song to declare openly ‘sex is fun’. According to it, several suggestive lines include a couplet from verse 4: ‘Moths in your rugs do it, What’s the use of moth-balls?’ and ‘Folks in Siam do it, Think of Siamese twins’. There’s also a report that Porter’s original version included the even more risqué line, ‘Roosters with a doodle and a cock do it’.
“Bing Crosby recorded two versions of ‘Let’s Do It’. The first, in 1928, was an uncredited performance with The Paul Whiteman Orchestra. In 1929, Crosby would be listed on the label as the vocalist of The Dorsey Brothers’ recording.”
The Paul Whiteman Orchestra, “Let’s Do It (Let’s Fall in Love)” (1928):
The Dorsey Brothers & their Orchestra with Bing Crosby, “Let’s Do It (Let’s Fall in Love)” (1929):