The song was written for Lennon's son Sean, his only child with Yoko Ono. It begins with John comforting his son from what is presumably a nightmare and develops into John passionately describing the love he has for his son and the joy Sean gave him.
At the end of the song, John Lennon whispers "Good night, Sean. See you in the morning. Bright and early." in a similar fashion to what Ringo Starr whispers at the end of the Beatles song "Good Night", which was a song written by John Lennon for his other son, Julian Lennon.
The lyrics of "Beautiful Boy (Darling Boy)" contain the famous Lennon quote "Life is what happens to you while you're busy making other plans." However, the expression of this sentiment can be traced back to a 1957 Reader's Digest article, which attributes it to Allen Saunders.
"Beautiful Boy" was recorded by Celine Dion for her album Miracle. It was released on 11 October 2004, in North America and parts of Europe as the first promotional single.
The song reached number two on the Quebec Airplay Chart. "Beautiful Boy" was also popular on adult contemporary charts, peaking at number 18 in the US and number 32 in Canada. It also reached number 30 on the Hungarian Airplay Chart.
In 2014, it was played during chapter 6 of the DreamWorks movie Mr. Peabody & Sherman as background during Mr. Peabody's journey through his memories of Sherman as he grew up. The end credits indicate Beautiful Boy was sung by John Lennon. The song was also included as track 7 on the movie soundtrack.