Paul McCartney was fond of the instrumentation of The Beatles’ “Lady Madonna.” The song’s instrumentation inspired Paul to sing like another rock star on the track. “Lady Madonna” became a hit twice in the United Kingdom.
The Beatles‘ “Lady Madonna” was Paul McCartney’s attempt to mimic boogie-woogie music. Paul said he was doing an impression of another rock star when he sang “Lady Madonna.” Subsequently, the rock star in question covered the track.
In the 1997 book Paul McCartney: Many Years From Now, Paul discussed the origin of “Lady Madonna.” “‘Lady Madonna’ was me sitting down at the piano trying to write a bluesy boogie-woogie thing,” he recalled. “I got my left hand doing an arpeggio thing with the chord, an ascending boogie-woogie left hand, then a descending right hand.
Source: cheatsheet.com