Isabella Acres is the voice actress for 13-year-old Princess Bubblegum, who first appears at the very end of "Mortal Recoil," and in "Too Young" until the end of that episode, when Princess Bubblegum is restored to her 18-year-old form, at which point Hynden Walch returns as her voice actress; she is also heard in archived audio, again as 13-year old Princess Bubblegum, in "Hero Heart." Her sister, Ava Acres, was the voice actress for young Marceline in "Memory of a Memory" and "Simon & Marcy." She is also the voice of Katie on Phineas and Ferb.
Episodes voiced in
- "Mortal Recoil": Young Princess Bubblegum
- "Too Young": Young Princess Bubblegum
- "Hero Heart": Young Princess Bubblegum (archived audio)