A freaky coincidence helped reunite South African parents with their daughter who was snatched from her mother's arms at a hospital almost 18 years ago, police said Friday, according to the Agence France-Presse.

Zephany Nurse was just three days old when she was stolen from her sleeping mother's arms at Cape Town's Groote Schuur hospital in April 1997.

The now 17-year-old, raised by a different family under a different name, was finally reunited with her real parents after students at her school noticed a striking resemblance between her and another girl- who turned out to be her biological sister attending her first year of high school.

Police spokesman Lieutenant-Colonel Andre-Traut told AFP a 50-year-old woman has been arrested for kidnapping Zephany.

"The suspect is being charged with kidnapping, fraud and contravening sections...of the Children's Act, in that she fraudulently pretended that she was the biological mother of a child."

Zephany's parents, Celeste and Morne Nurse, never gave up on finding their daughter. They celebrated her birthday every year, along with the birthdays of their three younger children, AFP reported.

When their 14-year-old daughter Cassidy started high school in January, students realized the eerie resemblance between her and one of the seniors. Cassidy found out about the senior, Zephany, and told her parents.

They invited the senior to their home for coffee. Cassidy's parents notified police once they also realized the resemblance.

Zephany and the family underwent DNA testing, the results proving she was Celeste and Morne's daughter. The parents had no idea their stolen daughter lived a short distance away all these years, AFP reported.

Police said the 50-year-old suspect and her husband, also in his 50s, had no children of their own.

"The kidnapped girl has since been placed in the care of the Department of Social Services of the Western Cape Government," Traut said.