Niall O'Dowd: Why Susan Boyle means so much to us... Click here

Susan Boyle got a standing ovation in London tonight as fans got to their feet to cheer her performance of "Memory" from the hit musical "Cats."

Boyle is now through to the final which will take place next Saturday after winning the popular vote and the judges' votes on "Britain's Got Talent."

This was the first time the singing sensation had performed live in front of such a huge audience.

Boyle was clearly nervous and fans around the world held their collective breaths as her voice quavered right at the start of the song.

However, within a couple of seconds she had regained her composure and her voice soon became crystal clear and strong.

She was more dressed up for the semi-final than she had been for the audition.

Her hair was more groomed and she wore a stunning bronze lace dress

She told the audience that she was just thrilled with the opportunity.

"All my life I've driven to prove myself. That I'm not just this little woman from Scotland. 

"I just want that chance to perform in front of the Queen."

She said the entire competition has been "absolutely unbelievable."

"What pressure?!" she said, "It was really good tonight. I've enjoyed every second. And I'd do it again."

Grouchy American Idol host and judge Simon Cowell gave Boyle the thumbs-up. "You are one special lady, you really are."

Poignantly, Boyle said a win would "prove that I am a worthwhile person."