Peter O'Toole allegedly upset his friend Richard Burton with taunts that the 'Where Eagles Dare' actor's wife Elizabeth Taylor had told him he was a better lover than her husband.
In new biography 'Peter O'Toole: Hellraiser, Sexual Outlaw, Irish Rebel', American authors Darwin Porter and Danforth Prince claim the late 'Lawrence of Arabia' star had an affair with Taylor when she was married to singer Eddie Fisher - her fourth husband who she tied the knot with in (May 1959 and divorced in March 1964 - and that it began with a tryst at the Dorchester hotel in London.
The thespian was great drinking buddies with Burton but their friendship was soured and "severely tested" when O'Toole reportedly confided to Burton he'd slept with his then spouse before they got together and boasted "she tells me I'm much better in the sack, at least more reliable, than you are".
The tome also claims that Taylor wanted O'Toole to star as Mark Anthony opposite her in the title role in 1963 epic 'Cleopatra'. The leading man role eventually went to Burton and it was on set that their love affair began.
Late Hollywood legends Taylor and Burton were married on two separate occasions from 15 March 1964 to 26 June 1974 and from 10 October 1975 to 29 July 1976. They had an adopted daughter, Maria Burton, together and Burton also adopted Taylor's daughter Liza Burton, who she had with producer Mike Todd.
In her lifetime, Taylor was married eight times to seven husbands, with her final marriage to Larry Fortensky ending in October 1996 almost 15 years before her death in March 2011 at the age of 79.
O'Toole's alcohol intake was the stuff of showbiz legend but the new tome - due to be published in June - focuses on his penchant for womanizing, and claims he had relationships with some of the most beautiful women of the 60s, 70s and 80s.
Some his alleged conquests - many of which occurred during his stormy 20-year marriage to Welsh actress Sian Phillips, whom he tied the knot with in 1959 - include April Ashley, the first British person to undergo a sex change operation, Audrey Hepburn, Vivien Leigh, Jayne Mansfield, Diana Dors and even royalty with Princess Margaret named as a notch on his bedpost.