"McCartney recorded a solo demo of the song on 24 July 1969, when he arrived early for an Abbey Road session. He sang the double-tracked lead vocal and played all the instruments: he sang and played piano on the first take, sang again and played maracas on the first overdub, drums came third and bass guitar was added last. It took less than an hour to finish.The demo appears on various bootlegs. It was officially released in 1996 on The Beatles Anthology 3 and issued under the Beatles name, even though McCartney was the only Beatle performing on the record."
"On 2 August 1969, McCartney presented his demo to Apple band Badfinger (then called The Iveys) telling them, "Okay, it's got to be exactly like this demo." His "carrot" for the band was his offer to produce this song and two other Iveys originals for the movie, since he had a contract to supply three songs for it. The band followed his instructions."
"McCartney auditioned each of the four Iveys to sing lead on "Come and Get It". Ultimately, he picked fellow Liverpudlian Tom Evans to be lead singer instead of the any of three Welshmen, Pete Ham, Ron Griffiths or Mike Gibbins."
"The single was released on Apple Records on 5 December 1969. "Come and Get It" was a hit single for the band in the United States, peaking at #7, and in the United Kingdom, peaking at #4. It was the opening theme for the film The Magic Christian, starring Peter Sellers and Ringo Starr (it was repeated in a scene in which people dive into a vat of human excrement to chase after money thrown into it). The biggest differences between the two versions are a slower tempo on McCartney's original and Badfinger's version featuring the use of three-part harmonies."
"The U.K. picture sleeve for the single shows all four members of Badfinger that appear on the song, although bassist Ron Griffiths departed the band before the single was released."