Princess Astrid of Freezenburg is Princess Hildegard's older sister. She was first seen in the flashback when Hildegard was singing the song Know It All and from the Sofia the First season two episode "The Princess Stays in the Picture". Later she made a cameo in "Princess Adventure Club".
Hildegard was singing about her bad first day at school when she was younger when she first mentioned her sister. When she was having a hard time making friends, she saw her big sister Astrid in the sun so she ran up to her and friends to be with them. The trio were doing their princess twirls and asked Hildegard to give it a try, but Hildegard didn't know how to twirl like them, so she fell down and Astrid's friends were laughing at her but not Astrid herself, because she was concerned for her younger sister.
- She was later seen in the beginning of "Princess Adventure Club", chatting with Prince Hugo, and she looked exactly the same as she did when Hildegard first came to Royal Prep.
- Her name hasn't been revealed on the show yet, but according to Craig Gerber, Astrid is her name.