Danny Boyle wrote Paul McCartney and Ringo Starr letters after landing Yesterday directing gig

Danny Boyle wrote letters to Paul McCartney and Ringo Starr after signing on to direct the musical comedy Yesterday.

The movie focuses on the story of struggling musician Jack Malik, played by Himesh Patel, who wakes up one day to suddenly realise he's the only person on Earth who can remember The Beatles.

Music from the iconic musicians features heavily in the film, and before Boyle began filming he wanted to notify the surviving members of the band – and the widows of George Harrison and John Lennon – about what he intended to do with their musical legacy.

"Once I got involved, I wrote letters to Paul McCartney and Ringo Starr, and the two widows, Olivia Harrison and Yoko Ono, respectfully laying out what I intended to do with the film. There’s obviously going to be nerves that somebody could be triggered or upset. But I got really lovely letters from Ringo and Olivia. I can’t talk about it except to say it was very special for me," he told Billboard.

However, there was one moment in the movie that divided fans, and Boyle himself called it a "Marmite moment".

As the film takes place in an alternate reality in which the foursome never become the iconic Liverpudlian band, Boyle explored the possibility that Lennon would still be alive, as he wouldn't have become famous and later assassinated by Mark David Chapman in 1980.

Trainspotting star Robert Carlyle plays the musician in the controversial scene, and the Oscar-winning director recognised that audiences would either love it or hate it.

"When we came to test the film, yes, there are some people that don’t like it at all. But other people like it enormously. We call it a ‘Marmite scene’ in Britain. It divides people very clearly," Boyle told USA Today.