The Beatles in-between recording.

Paul McCartney, London Heathrow Airport, 13th April 1967. Returns from America, where he has been celebrating the 21st Birthday of his actress girlfriend, Jane Asher.

The Beatles in-between recording

Paul McCartney performs with Brian Wilson and John and Michelle Phillips

In the early hours of this morning, after he was recorded chewing celery on The Beach Boys' song Vegetables, Paul McCartney returned to John and Michelle Phillips' house in Los Angeles, where he had been the previous day.

McCartney brought Brian Wilson back to the Phillipses' house, and various musical instruments were brought out. John Phillips also filled a tray of glasses with different amounts of water, and McCartney made sounds by rubbing the rims. He also played cello and flugelhorn at the house.

The jam lasted much of the early morning, and McCartney and Mal Evans returned to Derek Taylor's house in time for breakfast. McCartney and Evans then flew back to England, during which ideas for the Magical Mystery Tour film and songs were worked upon.

McCartney borrowed a notepad from a flight stewardess and drafted the lyrics for the Magical Mystery Tour song. He then drew a rough plan for the film, using a circle divided into eight segments to represent the 60 minutes of a television special.

Paul McCartney performs on The Beach Boys’ Vegetables

Paul McCartney and Mal Evans holiday in Denver

Paul McCartney and Mal Evans continued their stay in Denver, Colorado on this day, without Jane Asher who was appearing in a matinée performance of William Shakespeare's Romeo And Juliet in the city.

McCartney and Evans drove into the Rocky Mountains past Central City into the old Boodle Mine. During the trip their hired car got stuck in snow and mud, but they eventually made their way back to Central City and ate a meal in Paul's Café. Afterwards they watched a local country singer perform across the road in the Gilded Garter bar.

The pair returned to Denver in time to see the Old Vic theatre company's performance of Romeo And Juliet.

Studio Two, EMI Studios, London

The Beatles were mostly absent when the stereo mixes of Sgt. Pepper were prepared - they considered mono of paramount importance and so were always around for these, but were generally content to leave the stereos to George Martin and Geoff Emerick. Working this day from 7:00 pm to 1:00 am, they produced stereo masters of "With A Little Help From My Friends" (with its preceding crossfade into the title song). "Being For The Benefit of Mr. Kite!", "Fixing A Hole", and "Lucy In The Sky With Diamonds".

Sgt Pepper crossfades, Good Morning Good Morning

Paul McCartney visits Jane Asher in Denver

Paul McCartney flew to Denver from San Francisco on this day to pay a surprise visit to his girlfriend Jane Asher on her 21st birthday.

Asher was touring with the Old Vic theatre company in a production of William Shakespeare's Romeo And Juliet. McCartney had flown to America on April 3, 1967 with Mal Evans.

McCartney and Evans flew from San Francisco in a hired Lear jet; they arrived at Denver Airport and were met by Bert Rosenthal, who had agreed to lend McCartney and Asher his house. Evans, meanwhile, booked into the Driftwood Motel.

In the evening McCartney and Asher were reunited, and Rosenthal drove them to a hotel where a birthday party was held for her. The party had been organized by the Old Vic.