“It was about my observation of him and him being a dad, which was the most beautiful thing to watch,” she said.

“Once it was shared with a couple of friends and people that we were close with, they said, ‘No this resonates for me too because it feels really inclusive and there’s representation and it’s just like a sweet love story between a family’, and so I said, ‘OK let’s turn it into a children’s book’.”

She said she wanted to include the “softer side of masculinity” and to make sure “everyone felt like they could see themselves” in the pages, adding: “Because I remember, as a little girl, you didn’t always see someone who looked like you.”

The Duchess also told DeGeneres, with whom she has been friends for a few years, of her struggles as she tried to establish herself in showbusiness, revealing that when she went to auditions she had to climb into her car through the boot because the key had stopped working in the driver’s door.

The Ellen Show, which has run for 22 seasons, will end next year amid allegations of a toxic workplace culture.

Last August, DeGeneres, who dominates the daytime chat show scene, apologised following claims from dozens of former employees of sexual misconduct, bullying and racism among production staff.