Jezile's parents, Luyanda and Prudence, moved to England from the Eastern Cape over a decade ago.
Jezile is one of 12 performers who will take part in the finals of Simon Cowell’s ITV show on Saturday, where the winner will walk away with R3.8-million in prize money. The winner will be chosen by a public vote.
Messages of support from South Africa have been posted to the show's official Facebook page and on Twitter.
Sibongile Ngobese wrote: “Hey Luyanda, I saw Asanda on YouTube. I am so proud of her and wishing her all the best. Pity we cannot vote from South Africa. To all South Africans in UK, please support Asanda by voting.”
Buti Chuma wrote: “You making us very proud in South Africa. You are a girl child of the African soil.”
The London schoolgirl wowed the judges in the audition with a cover of Rihanna's Diamonds, but it was her version of Beyonce's Halo that won her a place in the final.
After the show, she said: “I chose to sing Halo because it is such a powerful song. I wanted to show the judges I am versatile."
Her parents have been supporting her every step of the way.
After she won her place in the final, her father told ITV: “I am so, so happy and proud of Asanda. There was really tough competition because there was a lot of talent. We had a little doubt that she would get though to the final because of that, but we always thought she could do it".