Why does Donald Trump say Fidel Castro could be Justin Trudeau's father? A look inside the WILD life of the Canadian PM's mother from her late night parties to risqué rumors - and links to the Cuban revolutionary

Rumors about Justin Trudeau's relationship with former Cuban president Fidel Castro have once again surfaced - this time in Donald Trump's latest book.

Fact-checkers have long dismissed the claim that the Canadian Prime Minister is the son of the late revolutionary leader - and both governments have been pressed to say the link is bogus.

But that has not stopped the former US president and Republican hopeful from repeating the myth in his latest work, 'Save America'.

Trump spends some time with the subject, recounting anecdotes as he sheds light on his relationship with the Canadian premier and digs into risqué rumors of Margaret Trudeau's relationships in the 1970s.

Scrutiny of her relationship with Castro around the time of her divorce rippled through the internet in 2016 - but rumors were largely debunked by 2018, making Trump's 2024 revival of her alleged 'association' unusual.

With the Republican candidate's interest in Justin Trudeau back in the spotlight, DailyMail.com takes a look at the claims - and the wild allegations included in Trump's book.

Justin Trudeau is the son of late former Prime Minister Pierre Trudeau and activist Margaret Sinclair. He was born in 1971 and his parents divorced 13 years later, during his father's last months in office.

Margaret Trudeau would later admit - in her 1982 book Consequences - that she had had affairs with actors Jack Nicholson and Ryan O'Neal, and singer Lou Rawls as the relationship broke down.

And through her public persona she said she became associated with members of the Rolling Stones, top US government officials - and even Cuban revolutionary leader Fidel Castro.

The latter of these relationships became the subject of a conspiracy theory after Castro's death in 2016, with netizens pointing to physical similarities between the two world leaders. 

Trudeau also received backlash when he praised the controversial leader as a 'larger than life legendary revolutionary' in remarks after his death.

Theories exploded when Castro's eldest son, Fidelito, died by suicide in 2018 and several outlets reported he had left a note referring to Trudeau as his half brother.

An entertaining break-down from VICE observed: 'The conspiracy was of course then amplified by 4Chan trolls, far-right blogs, and the worst people on Twitter who all took this as fact and worked to further the theory. 

'The theorists went deep, like trying to approximate Margaret Trudeau’s menstrual cycle deep, and it is all very, very stupid.'

Photos have emerged of Fidel Castro holding Justin Trudeau in 1976 as the Canadian Prime Minister and his wife landed in Havana in a historic visit, becoming the first NATO leader to step foot in Castro's Cuba.

The leaders reportedly got on 'famously' and developed a close bond in the years that followed.

But there is no evidence Margaret or her husband had met Castro before Justin was born.

'Experts say it would have been impossible for an earlier visit to Cuba to go unnoticed,' the AP noted in 2018.

'Cuban media have been unusually open about the death of Castro's oldest son, Fidelito, describing it as a suicide after a long depression. 

'Neither state media nor independent reporters covering the death have reported the existence of a suicide note.'

This did not stop Donald Trump from entertaining the rumors in his new book, however.

The former President wrote: 'His mother was beautiful and wild. In the 1970s, she would go 'clubbing' with the Rolling Stones, but she was also somehow associated with Fidel Castro. 

'She said he was 'the sexiest man I've ever met,' and a lot of people say that Justin is his son.

'He swears that he isn't, but how the hell would he know! 

'Castro had good hair, the 'father' didn't, Justin has good hair, and has become a Communist just like Castro.'

Such rumors prompted the Canadian, and Cuban, government to issue denials following the death of Castro. Factcheckers supported their claims.

The Associated Press was among those debunking the theory, noting that Trudeau was born around four years before Margaret made her first trip to Cuba. 

Margaret's relationships with other political leaders, entertainers and celebrities have also been a source of curiosity over the decades, guided by her own admissions of affairs during her relationship with Pierre.

In May 1977, rumors that their marriage had fractured erupted after Margaret was spotted partying with the Rolling Stones until the early hours of the morning. 

While reflecting on the incident to Harper's Bazaar in 2016, Margaret explained that she and Pierre had already been separated in secret when the wild night out occurred.

'We played dice until about five in the morning in my hotel suite, smoked some dope, talked. It was a good night, and it was my new world,' she said.

'But no one knew I was separated from my husband yet, and it brought a huge scandal.'

The couple announced that they were divorcing soon after, with Pierre stating at the time that Margaret 'wished to leave the marriage and pursue an independent career.'

Still, she reflected in 2016 that she felt she had unfairly assumed much of the blame for the relationship breaking down.

'I didn't walk away. It was mutual. Any woman would have [done the same],' she explained.

'Any mother who wanted to protect her children from the isolation that Pierre lived in, and his disdain for anyone crowding him, which is what we call friends.'

Still, the rumors of any intimate relationship with the Rolling Stones have been dismissed.

'It's really embarrassing. It just isn't true, ya know?' Stones frontman Mick Jagger said at the time. 

'She just came for a two-night concert. She just wanted to have a good time. I dunno.'

He later told the Evening Standard she was a 'very sick girl in search of something. She found it - but not with me. I wouldn't go near her with a barge pole.' 

Trump White House Press Secretary Stephanie Grisham also noted in her own memoirs that Margaret denied having affairs with any of the Rolling Stones. 

But Trump allegedly leaned into the potentially damaging rumors, Grisham recounted in her book.

She claimed that Trump once repeated the rumor about Margaret's relationship with the British rock band.

'Once, on Air Force One, I was sitting with him in his cabin, and for whatever reason — maybe he had just read something or seen his face on TV — Canadian prime minister Justin Trudeau popped into the president's head,' Grisham wrote.

Trump then asked, 'Are you OK if I say this?' according to Grisham, before blurting out: 'Trudeau's mom. She f***ed all of the Rolling Stones.'

'I was hardly a woman, in my early 20s' Margaret Trudeau would later reflect on her marriage to Pierre Trudeau, explaining the real reasons behind their split.

'He was a very urbane, sophisticated intellectual in his early 50s.'

'I was fresh out of university. I was a flower child. I was very free-thinking for my time. I had been raised to be very liberated...

'But once he married me and got me home and I was having his children, I realized that I had been put in a birdcage.'

The pair agreed to separate in 1977 and divorced in 1984, when Trudeau was barely a teenager.

Margaret has been candid about her relationships with various celebrities as she became a public persona and socialite in her own right.

But rumors about her alleged relationship with Fidel Castro, and claims he fathered the incumbent Canadian Prime Minister, remain wholly unfounded.