John Lennon’s son Julian was shocked by his father being brought “back to life” during Sir Paul McCartney’s shows. Lennon has been digitally ‘resurrected’ using video and artificial intelligence to perform duets with Sir Paul, including one of the 1969 track ‘I’ve Got A Feeling’ at the singer’s Glastonbury headline slot this year. The stunt was masterminded by The Beatles documentary ‘Get Back’ filmmaker Peter Jackson, who used “machine learning technology” to isolate Lennon's vocals from old recordings and arrange them into a copy of a live performance.