A virtual version of the handwritten notes for the song "Hey Jude" has been sold at auction in California for almost $77,000, the latest hammer price success for NFTs.

Originally entitled "Hey Jules", the Fab Four's hit was written in 1968 by Paul McCartney to comfort a young Julian Lennon during father John's separation from his mother, Cynthia.

The NFT version of the notes was presented as an animation in which the words are progressively inscribed on the page and was accompanied by an audio commentary from Lennon junior.

"For me, just looking at a picture is not enough if I was a buyer," Lennon earlier told AFP in Los Angeles.

"So I wanted to add something a little more personal. And for me, that was writing and narrating a little bit of story that would be behind the images."

The sale, by Julien's Auctions, also included an NFT of the Afghan coat worn by his father on the set of "Magical Mystery Tour," which fetched $22,400

NFTs, or non-fungible tokens, are unique digital objects that confer ownership.

While their content may be copyable, the NFT is "the original", in much the same way that there are innumerable prints of Leonardo da Vinci's "Mona Lisa", but only the Louvre museum has the original.

Investors and wealthy collectors have clamored in recent months to get involved in the latest digital craze, which relies on the same blockchain technology that powers cryptocurrencies and cannot be forged or otherwise manipulated.

Recent auctions have seen eye-watering sums paid for NFTs, including a staggering $69.3 million for a digital work by artist Beeple at a sale at Christie's.