“Let’s figure out what our letter of the day is!”

Ms. Rachel, the children’s YouTube star, cooed that sentence in an Instagram video posted this week as she dug into a sensory bin of purple rice, with the kind of texture toddlers tend to ogle.

Set against a blank yellow screen, like many of her videos, she smiled as her ponytail bobbed onto her signature pink T-shirt and blue overalls.

She gasped as the camera panned to a bright red “N” in the rice.

Holding the letter, she cheerfully told viewers in her singsong voice that her videos would soon be available on Netflix.

The announcement is the latest development for the booming empire of Ms. Rachel, the child educator from Maine turned viral video star, whose appeal has been compared to that of Mister Rogers and Beyoncé.

She has more than 13 million subscribers on her YouTube channel and millions more on Instagram and TikTok, with her videos have collectively drawn billions of views.

Ms. Rachel, whose full name is Rachel Accurso, also has a multibook deal with Random House; a line of toys, including a popular cooing doll in her likeness; and branded T-shirts, pajamas and bathing suits. She works with her husband, AronAccurso, the co-creator and co-producer, and they are represented by the powerhouse talent group Creative Artists Agency.