It's called 'Wonderful Christmastime,' and if you've ever been to a mall between Thanksgiving and New Year's, you have definitely heard it. Paul McCartney's contribution to Beatles-adjacent holiday canon came in 1979. John Lennon, of course, released the immortal 'Happy Xmas (War Is Over)' in 1971, George Harrison dropped his New Year's banger 'Ding Dong, Ding Dong' in 1974, and Ringo Starr finally recorded an entire Christmas album in 1999 called I Wanna Be Santa Claus featuring a single of the same title.
Each of the Beatles eventually got around to recording a holiday song sooner or later after their breakup.
