More than a dozen students went Walker's home after school on Wednesday and sang Hillsong's "Oceans."
Cindi Lee Cooper - Fields recorded the heartwarming moment.
Alvin students sing outside dying teacher's home
"(Her family) opened the doors so she could hear them sing," said Cooper - Fields. "It was one of the most beautiful gestures I have ever seen. Friends from all ages got together and sang like angels in hopes of her feeling our love and respect we all have for her."
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Once the students were done singing, they said a prayer and their final goodbyes.
"The family walked back in the house and within a few minutes she took her last breath," said Cooper - Fields.
Walker died just moments after the song.
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"Knowing Mrs.Walker you knew she wasn't going to leave us until the show was over," said Cooper - Fields.
Funeral services for Walker are scheduled for Monday.
WATCH: Cancer-stricken teacher serenaded by 400 students dies