The 20-year-old star will be taking over the lead role in the stage musical Cinderella next month, reported Vanity Fair.
"I don't really celebrate. And besides, I still don't believe it is real!," Palmer said when asked how she was celebrating her casting.
Palmer will debut as Cinderella on September 9. She will spend the next month rehearsing.
The young star will be replacing Cindy Paige Faure in the role of the popular heroine, who is serving as a servant, before finding her Prince Charming with the help of a pair of see-through shoes.