Susan Boyle topped off a tumultuous week with a superb performance at the finals of Britain's Got Talent tonight in London.

Singing the song that made her famous, “I Dreamed A Dream” from “Les Miserables,” she again wowed the audience and the judges.

Judge Piers Morgan hailed her song as “the greatest performance” in the reality competition’s history.

“That to me was the greatest performance I’ve seen in ‘Britain’s Got Talent’ history… you should win. I loved it,” Piers said.

Another judge, Amanda Holden, was close to tears. “You did it, girl, you did it for Scotland,” Amanda said adding that American Idol judge Simon had "a tear in his eye.”

Cowell himself also paid tribute to Boyle's determination saying he "absolutely adored" her.

"You could have walked away [from the competition] and you could have had a lot of stuff coming your way in America,” Simon said.

“Win or lose, you had the guts to come back here tonight, face your critics and you beat them and that’s the most [important] thing…. You can walk away with your head held high. I absolutely adore you.”

He said he was glad to have met the “real Susan Boyle,” who he described as “a very nice, shy person who deserves a break.”

Boyle, whose parents Patrick and Bridget both came from Ireland has said that the death of her mother had inspired her to enter the TV talent show.

"I wanted to show her I could do something with my life," Boyle said.

Now, the world is waiting tonight to see if Boyle will win the final.