The Beatles star tickled the ivories in a electrifying duet with Motown founder Berry Gordy, playing a rendition of the famed record label's first hit, 1959's Money (That's What I Want), which was later covered by the Fab Four.
MCCartney spotted the dilapidated 1877 Steinway grand piano, which has been played on classic tracks by stars including Stevie Wonder and Marvin Gaye, during a tour of the new Motown Museum last year (11).
The Hey Jude hitmaker got in touch with makers Steinway & Sons and made arrangements to have the instrument shipped to New York for a full refurbishment.
Experts replaced strings, hammers, legs and other parts to restore the piano, which is hailed as one of the many instruments that helped create the legendary 'Motown Sound'.
MCCartney told the 100-plus industry dignitaries in the audience at the event on Tuesday, "We were wandering around Studio A inside Motown Museum, when I saw this piano. I thought, 'I can't come to Motown and not tinker on it'.
"Once I realised it was unplayable, I called Steinway & Sons and they also realised... this piano was part of a major moment in history. And now people in the future will record on it and keep the legacy of Motown alive."