The 49-year-old devout Catholic fulfilled a lifelong dream by performing for Pope Benedict XVI – the head of the Catholic Church -in an open-air ceremony in Glasgow, Scotland.
An excited Susan fainted 24 hours earlier when told she would be singing for the pontiff.
But when it came to the performance, the singer – who shot to global fame after appearing on TV talent show 'Britain's Got Talent' - turned in a flawless display with a rendition of her most famous track 'I Dreamed a Dream' from the musical 'Les Miserables'.
She then performed a stirring rendition of hymn 'How Great Thou Art' and finished with 'Make Me a Channel of Your Peace'.
Susan – who sang before and after the Papal Mass - said: "It's something I've always dreamed of, it's something I've always wanted to do, and here I am, finally getting the chance."
The 65,000 crowd were enthusiastic about her appearance.
Marie-Alice Quigley, 60 - who travelled from Gorebridge, Midlothian, to see the pope - said: "I thought she was marvellous. She was every bit as good as she's made out to be."
Susan has previously admitted she was "humbled" to be asked to sing for the pope during his four-day visit to the UK.
She said: "The pope's visit is a very big event for Scottish Catholics. My own faith is the backbone of my life, I pray and say the rosary each day and am very close to my religion."