Prince Louis loves his scooter.
The royal youngster's parents, the Duke and Duchess of Cambridge, "can't keep up" with their three-year-old son when he's out whizzing around on his favourite toy because he's "very quick" on wheels.
During a phone call with a finalist from her 'Hold Still' photography project - which was recorded in autumn 2020 but released on Thursday - Catherine told four-year-old Mila: "Louis has got so big now, he's very quick running around and he's on his little scooter as well. He's very quick. I can't keep up with him."
Elsewhere during the call with Mila and her mother, Lynda Sneddon, Catherine promised the youngster she'd wear a pink dress if they ever get chance to meet in person.
Mila asked the duchess: "Do you have a costume?"
Catherine replied: "I'm not wearing a princess costume right now, I'm afraid Mila. Do you have lots of dressing-up outfits yourself?”
When Mila said she did and told Catherine her favourite colour was pink, the duchess replied: "OK, well I have to make sure I go and try and find myself a pink dress so that hopefully, when one day hopefully, Mila we'll get to meet and then I'll remember to wear my pink dress for you. Would that be nice?"
Mila and her mother isolated from the youngster's father Scott and older sister Jodi during the coronavirus pandemic to minimise risks to the little girl as she was receiving chemotherapy to treat acute lymphoblastic leukaemia.
The photo they submitted for 'Hold Still' featured Mila kissing the window as her dad stood outside.
'Hold Still' was launched in May 2020, when the duchess invited people in the UK to submit their photos that captured their time during lockdown, with 100 images displayed in a digital exhibition on the National Portrait Gallery's website and later compiled into a book.
Catherine previously said of the initiative: "When we look back at the Covid-19 pandemic in decades to come, we will think of the challenges we all faced – the loved ones we lost, the extended isolation from our families and friends and the strain placed on our key workers.
"But we will also remember the positives: the incredible acts of kindness, the helpers and heroes who emerged from all walks of life, and how together we adapted to a new normal.
"Through 'Hold Still', I wanted to use the power of photography to create a lasting record of what we were all experiencing – to capture individuals' stories and document significant moments for families and communities as we lived through the pandemic."