"Happy Xmas (War Is Over)" is a song by English singer-songwriter John Lennon with Yoko Ono. [. . .] The lyrics are based on a campaign in late 1969 by John Lennon and his wife, Yoko Ono, who rented billboards and posters in eleven cities around the world that read: "WAR IS OVER! (If You Want It) Happy Christmas from John and Yoko." The cities included New York, Tokyo, Rome, Amsterdam, and London. At the time the United States was deeply entrenched in the unpopular Vietnam War. The line "War is over/If you want it/War is over/Now!", as sung by the background vocals, was taken directly from the billboards.

The record starts with a barely-audible whisper: Yoko whispers "Happy Christmas, Kyoko," then John whispers "Happy Christmas, Julian." Kyoko is Yoko's daughter (from her marriage to Anthony Cox), and Julian is John's son (from his marriage to Cynthia Lennon). Both children were 8 years old at the time the song was recorded in 1971.

Directly following John Lennon's death on December 8, 1980, the song was re-released in the UK on December 20 of that year.

Listen to the song via Crooks and Liars here.