Ms Spencer's reaction was widely criticised on Twitter, with U.S. actor Rosie O'Donnell describing her laughter as "like bullying on national TV". The clapbacks came quickly and Spencer eventually apologized, but not before she was met with comments from famous faces from the stage and screen.
Spencer then claimed William said his son "absolutely loves ballet".
"In addition to the usual 1st or 2nd grade things like math, science and history, the future king of England will be putting down the PlayDough to take on religious studies, computer programing, poetry and ballet among other things", Spencer said Thursday on Good Morning America, and laughter ensued.
Director and choreographer Debbie Allen, who worked on 80s TV show Fame, said "this is just not cool".
"Darling you're not on Saturday Night Live, you're a respected media journalist". Just think about the young boys who may have seen this and could quit their passion at her expense.
"We'd get more Steve Jobs if we had more ballet - less bullying."
She is teaching the word that it is ok to laugh at boys for dancing and that is so sad.
Twitter users were quick to point out that many men from Spiderman's Tom Holland to Patrick Swayze and even Tupac Shakur took ballet lessons as children.
Several news outlets, including Broadway World and Dance Magazine, echoed Allen's sentiments and demanded an apology.
"This adorable boy (Prince George) is being shamed by a grown woman on National Television in America for taking ballet!"
Spencer issued an apology on Friday, writing on Instagram, "My honest apologies for an insensitive comment I made in pop news yesterday".
"From ballet to anything one wants to explore in life, I say go for it". I fully believe we should all be free to pursue our passions.
THR explains that Prinve George's dance classes follow the Royal Academy of Dance syllabus and he's learning the basics of ballet with a pianist providing musical accompaniment.
"We'll see how long that lasts", Spencer deadpanned before chuckling. "You keep at it".
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