Kate and William were nervous when they stepped outside the Lindo Wing of St Mary's Hospital in London in July 2013 with newborn George.
"It was slightly terrifying, I'm not going to lie," Kate said. She said they tried to rehearse for the moment ahead of time by practising with a doll, but nothing prepares you for the actual moment: Do you swaddle or not? What is the best way to hold the baby? How do you wrangle an unwieldy car seat into the back seat?
"This was sort of something that everyone was excited about and we were hugely grateful for the support that the public had shown us," she said. "And for us to be able to share that joy and appreciation with the public I felt was really important. But equally, it was coupled with a newborn baby and inexperienced parents and the uncertainty of what that held, so there were all sorts of mixed emotions."
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2. Labour was better than pregnancy, in some ways.
Remember that the duchess had hyperemesis gravidarum, an extreme form of morning sickness, during all three pregnancies.
"I was not the happiest pregnant person," she said. "I was really sick, I wasn't eating the things I should be eating."
She used mind-over-body exercises to cope with the illness while she was pregnant, she said, then turned to hypnobirthing - a practice where women use self-hypnosis and relaxation techniques to reduce anxiety and pain during labour and childbirth - which she found helpful.
"Because it had been so bad during pregnancy, I actually really quite liked labour," she said. "It was something, it was an event that I knew there was going to be an end to. But I know some people do have really difficult times."
3. She stresses strong relationships - especially in tough times.
The duchess spoke fondly of time spent with her grandmother when she was a child.
"I had an amazing granny who devoted a lot of time for us, playing with us, doing arts and crafts, and going to a greenhouse and doing gardening and cooking with us," she said. Those are all experiences she tries to replicate with her own children: simple, quiet moments where they are focused solely on each other.
But she acknowledged that busy schedules and highs and lows of parenting - and life - can make that challenging. It's important for parents and children to have a strong network of other loving adults, she said, particularly when times are tough.
"We all have good days, bad days, and actually if you can dilute that with others who aren't on that particular day struggling, I think it makes such a difference."
4. She's happiest when she's outside, "filthy dirty" with her family.
For her last question, Fletcher asked the duchess when she is happiest.
"When I'm with my family outside in the countryside and we're all filthy dirty." It was a somewhat (but not totally) unexpected answer from someone who is expected to look impeccable any time she appears in public. But it's also true to brand from the royal who has designed play gardens for children and publicly campaigns for time in nature as a critical component to mental health.
"We spend an awful lot of time outside, and it's something I'm passionate about," she told Fletcher. "I think it's so great for physical wellbeing and mental wellbeing and actually laying those foundations." She referenced a photo she took of Charlotte smelling a bluebell as the type of experiences she wants her children to have more of. "I try every day to put moments like that in, even if they're small, even if I don't have time."
She said simple times with children, including time in the outdoors, are a great way for adults to combat the stress of busy modern lives.
"You can get so distracted and put so much pressure on yourself about the things you're not necessarily achieving, and it distracts you from the things that really do matter: the lifelong health and happiness of the children that you're looking after."