The moment this 11-year-old girl realizes her foster family has adopted her is pure joy

It's a moment of pure joy committed film: A young girl realizing she would be adopted, letting her foster family become her permanent one.

Security footage from at American Heritage School in South Jordan, Utah, shows the moment when 11-year-old Tannah Butterfield learned from Jackie Alexander, her school's office manager, that courts had approved her adoption, Alexander wrote on Instagram. 

Alexander had received a call moments earlier from Tannah's mother about the news.

"She knew she would want to know right away because she had been so worried," Alexander wrote. "I don't think even I could understand myself what that moment would feel like."

Tannah flings herself into Alexander's arms, kicking her legs in excitement as she's carried across the room. 

Alexander said Tannah's parents had fought to adopt her "for as long as I can remember," and Tannah told CBS News she dreamed of the moment for years

"They are just caring, loving, they take really good care of me," she said.  "My heart was so happy, it was like, 'Ahhh!' It was screaming."

More: Mickey surprises kids with adoption day at Disney World

More: She thought she was an only child. She got the surprise of a lifetime.