The new Harry and Meghan biography claims that Charles' 70th birthday photograph was an 'absolute nightmare'

The new Prince Harry and Meghan Markle biography, Finding Freedom, has made a number of claims about the couple, from the phone call that changed everything to the real story behind the reported wedding tiara drama.

Now, the unauthorised edition by authors and royal correspondents Omid Scobie and Carolyn Durand claims that Prince Harry and Prince William 'can be hot and cold with their father', Prince Charles.

It also alleges that the photoshoot for Charles' 70th birthday portraits - featuring himself alongside Camilla, Duchess of Cornwall, Prince William, Kate Middleton, Prince George, Princess Charlotte, Prince Louis, Prince Harry and Meghan Markle - was 'an absolute nightmare'. While the photographs show the family smiling and laughing, it is said to have been difficult to organise due to the rumoured feud between the royal brothers.

Things are said to be even more 'complex' as their father is also their boss.

The book reads: '"The boys can be hot and cold with their father," disclosed a source, who gave the example of planning the photo session for Charles' 70th birthday, which they called "an absolute nightmare".

'"Neither William nor Harry made much of an effort to make themselves available," the source said.'

It is also claimed that financial disagreements led to tensions, as Charles must 'control the purse strings' when it comes to his sons.

The authors write: 'The brothers sometimes had to vie for additional funds for projects from their father, who also helped to cover expenses related to Camilla and some of those for his sons (including Kate and Meghan's wardrobes).

'"They actually genuinely have to debate who gets what amount from their father to fund their projects," an aide said.

'While Charles may be a father to Harry, he's also their boss, and that makes their relationship complex for a number of reasons.'

Harry and Meghan have denied any involvement with Finding Freedom.