As Markle is now expecting her first child with Prince Harry, the musical will no doubt address the couple's exciting new journey, though the short special will also tackle the Duchess' life before becoming a mom.
Pregnant Meghan, 37, visited King's College London, but her trip was not announced.
The women both turn away from each other - Meghan looks at the floor with a sheepish smile, Kate looks at her husband for support, and William takes the reigns and laughs, saying "Ooooh, yeah".
It's easy to wonder why the palace would comment on a news story - doesn't a denial just make the original story seem so much more valid?
Harry added that they 'come so thick and fast'.
"We don't [send her the whole line] because some of that stuff we know is like, OK, maybe she wouldn't be looking at the colorblock trousers because I don't know if it's appropriate", the Olympic athlete joked.
The friction between the two apparently started when William tried to give Harry some brotherly advice about the Canadian actress, back when their romance was still fairly new.
She said: "Like me, Meghan probably never dreamt that she'd have a life like this, and the pressure you feel - from yourself and from others - can sometimes feel like a lot".