Giovanna Fletcher discusses interviewing 'dream guest' The Duchess of Cambridge

Giovanna Fletcher has admitted she "didn't sleep" before having Catherine, The Duchess of Cambridge, on her Happy Mum, Happy Baby podcast.

Catherine, 38, made a guest appearance on the Early Years episode last week to raise awareness of her Five Big Questions survey - which has been created to learn more about the habits of parents and children up and down the country.

Although Catherine has been a "dream guest" of Giovanna's for a while now, the mum-of-three boys said that only added to the pressure of interviewing a member of the royal family.

On whether she was nervous prior to the chat, Giovanni said, "From day one, yes. The week before, I literally wasn't sleeping. Because she'd been on my wish list for so long, and my dream guest, it's one thing to actually want someone on and then to get them and go, 'Oh my gosh, that comes with so much responsibility.'"

But Giovanna - who is married to McFly star Tom Fletcher - kept her nerves at bay by meticulously planning the podcast, just like she would with any other guest.

"As soon as I started planning out the episode... and what I do every time is I map it out, write loads of questions and then I don't look at the paper at all and just enjoy the chat, just kind of get lost in it," she told Christine Lampard, who was standing in for Lorraine Kelly on Lorraine.

And Giovanna reminded herself that as well as being The Duchess of Cambridge, wife to Prince William and mother to an heir to the throne, Catherine is simply a mother at heart. Which she described as a "leveller".

"As soon as I started remembering that I was just talking to another mum, everything else sort of made sense," she explained. "That's what the podcast's all about. It doesn't matter who you are, what you have, what you do - there are so many parts of motherhood that we can all relate to, and it's a complete leveller."

And the pair quickly bonded over the "lack of sleep" that all mother's can relate to. "We were talking about lack of sleep - literally, it just gets you, it takes over."

Like Giovanna, Catherine is also a mother of three to Prince George, six, Princess Charlotte, four, and one-year-old Prince Louis. Opening up on the podcast, Catherine confessed to feeling "mum guilt" and said it can be a "constant challenge" balancing motherhood and work.

She explained, "Yes absolutely – and anyone who doesn't as a mother is actually lying! Even this morning, coming to the nursery visit here – George and Charlotte were like, 'Mummy how could you possibly not be dropping us off at school this morning?'"