But her YouTube video is now one of the most watched on the site and last week she was invited to play in front of Singapore's Prime Minister Lee Hsien Loong.
Agencies report that she was bandoned at birth but was adopted by a wheel-chair bound man and his infertile wife in South Korea, where her story and talent have made her a household name.
Her family say she was given an old piano by a neighbour and at the age of three, surprised her parents by suddenly playing a Korean song that her mother loved to sing.
Her parents then started playing different pieces of music for her from the internet, and said they were shocked to discover that she could play every tune after hearing it.
Yoo has appeared on the popular "Star King" Korean television talent show and won the three million won ($3,900) cash prize.
Her performance, which was posted on a Korean-based video sharing website, has attracted more than 27.5 million hits as well as over two million viewings on Youtube.
Watch the video here:
- Various agencies
