Grace Bonamico had not seen her sister, Colleen, since Colleen left for technical training school in August.
Colleen showed up at Grace's classroom at Wst Babylon Junior High -- and it was an emotional moment for both of them.
Watch raw video from the surprise, as well as the full interview with the sisters here:
Colleen is a 2017 West Babylon graduate and an airman first class stationed in San Antonio. She'll get to spend some time with family before leaving on her new assignment on January 3.