John Lennon's son has described the "proudest day" of his life as his mother, Yoko Ono, was officially named co-writer of the 1971 hit Imagine.
Sean Ono Lennon attended a ceremony by the National Music Publishers Association (NMPA) on Wednesday as his late father's famous single was honoured with the organisation's centennial song award.
As he helped his wheelchair-bound mother, 84, on to the stage to accept the prize at the New York event, NMPA chief executive David Israelite declared the song a Lennon-Ono creation for the first time.
Lennon, 41, took to Facebook to describe how his mother broke down in tears as an old interview with his ex-Beatle father was played, crediting her inspiration.
Speaking more than 45 years after the song's first release, he added that "patience is a virtue".
Sharing a photo of the pair with Patti and Jesse Smith at the event, he wrote: " Proudest day of my life: The National Music Publishers Association just gave the centennial (song of the century) award to Imagine, but WAIT! Surprise!
"They played an audio interview of my father saying (approximately) 'Imagine should've been credited as a Lennon/Ono song, if it had been anyone other than my wife I would've given them credit.'
"Cut to: my mother welling up in tears, and then Patti and Jesse Smith played Imagine! Patience is a virtue! (PS then they officially declared Imagine to be a Lennon/Ono song!)
According to Variety magazine, Yoko said that a current illness had made her appreciate the emotional song more fully and added that the moment marked "the best time of my life."
Billboard reported that the BBC interview clip of John Lennon showed him telling how the "lyric and the concept" of the song came from words in Ono's 1964 book, Grapefruit.
"Those days I was a bit more selfish, a bit more macho," he said. "I sort of omitted to mention her contribution."