They may have got by with a little help from their friends in 1967, but four years later, relationships had soured between John Lennon and Paul McCartney, as a vitriolic letter from the former now shows.
An undated letter thought to have been written by Lennon in 1971 is up for auction for $20,000 (£16,000) with RR Auction.
Addressed to "Linda and Paul", the typed letter - which has a letterhead of the faces of Lennon and his wife, Yoko Ono - doesn't hold back in addressing the recent break-up of The Beatles, and Lennon's relationship with the press and with Ono.
It's thought to be a response to a letter Linda McCartney had sent Lennon, chiding him for not openly announcing his departure from the band.
The Beatles publicly broke up in 1970, although Lennon left the band in September 1969 following a combination of the death of their manager, Brian Epstein, legal tussles over their record label and business Apple Corps, and McCartney and Lennon meeting Linda and Ono, respectively.
Lennon explains that he didn't make his departure public because:
"Paul and Klein [Allen Klein, The Beatles' new manager] both spent the day persuading me it was better not to say anything - asking me not to say anything because it would 'hurt the Beatles' - and 'let's just let it petre out' - remember? So get that into your petty little perversion of a mind, Mrs. McCartney - the c*** asked me to keep quiet about it."
With regards to his and Ono's relationship, Lennon writes:
"I hope you realise what shit you and the rest of my 'kind and unselfish' friends laid on Yoko and me, since we've been together. It might have sometimes been a bit more subtle or should I say 'middle class' - but not often. We both 'rose above it' quite a few times-& forgave you two-so it's the least you can do for us-you noble people."
Lennon goes on to justify speaking to the press about the fall-out with McCartney and his new ventures with Ono:
"Excuse me if I use 'Beatle Space' to talk about whatever I want - obviously if they keep asking Beatle questions - I'll answer them - and get as much John and Yoko Space as I can - they ask me about Paul and I answer - I know some of it gets personal - but whether you believe it or not I try and answer straight - and the bits they use are obviously the juicy bits - I don't resent your husband - I'm sorry for him. I know the Beatles are 'quite nice people' - I'm one of them - they're also just as big bastards as anyone else - so get off your high horse! - by the way - we've had more intelligent interest in our new activities in one year than we had throughout the Beatle era."
The Imagine songwriter also takes the opportunity to insult Linda's family, even suggesting the McCartneys' marriage would be over in two years:
"Of course, the money angle is important - to all of us - especially after all the petty shit that came from your insane family/in laws - and GOD HELP YOU OUT, PAUL - see you in two years - I reckon you'll be out then."
Finally, he signs off: "inspite [SIC] of it all, love to you both, from us two".
The letter was last up for sale in 2011, when it had an asking price of $40,000.