"Prince William says George absolutely loves ballet, I have news for you Prince William we'll see how long that lasts," she said, attempting to stifle her giggles.
Her comments have caused outrage among viewers, and celebrities have since spoken out against her "outdated" views.
"What a shameful, outdated, harmful attitude being broadcast to the masses. Dance has countless scientifically proven benefits for physical and mental health," wrote former Strictly judge Arlene Philips on Instagram.
"There should be nothing but encouragement for any male who chooses to try dance whether it's as a fun hobby or for a future as a professional."
Rosie O'Donnell also shared a video slamming Spencer for her comments, and Twitter users pointed out the numerous famous men who have taken dance lessons.
Many also encouraged the TV presenter to watch the movie Billy Elliot to bring her thoughts into the 21st century.
After the backlash, Spencer took to Instagram to issue an apology.
"My sincere 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. Go climb your mountain - and love every minute of it," she wrote.
As part of his school St Thomas's Battersea's education programme, Prince George will have 35-minute ballet classes, which are accompanied by a live piano player.
Last year, Prince William told BBC Radio his eldest son was a "keen dancer" like his late grandmother Princess Diana, and had been loving his ballet lessons at school.
