John Lennon hit his son Julian, his former housekeeper claimed.
A statement written by The Beatles' star's former domestic worker Dorothy Jarlett about John's behaviour during his split from first wife Cynthia Powell has been unearthed following her death last year, and suggests the musician was violent towards his son, born in 1963.
In the five-page document - written in 1968 - Dorothy explained how the late rocker, who was shot at the age of 40 in 1980, was "too severe" with the couple's son when he was a youngster which frequently led to explosive arguments.
She wrote: "When Mr Lennon was at home there were often rows during meals when John seemed to be too severe with Julian and criticised the way he behaved at table.
"Julian, who was a very sensitive child at the time, would become upset and Mrs Lennon would argue with Mr Lennon about this. As a result there would be an argument about the way Julian was being brought up.
"Mr Lennon would say Mrs Lennon was too soft with him. I think he was probably not enough with his son owing to his profession to know how to handle him."
A line at the end of the document which was then crossed out reads, "As a result he would often smack him."
The statement was written for John's divorce solicitors when he was seeking a separation from Cynthia in order to marry his mistress, Yoko Ono, who he wed the following year and had a second son, Sean, with.
The document is set to be auctioned off next month and is expected to receive bids of up to £5,000.