Britain's Got Talent judge Amanda Holden says viewers are finally getting to see the "real Simon Cowell."
She said the presence of Little Britain star David Walliams on the judging panel had brought out a different side of the show's supremo.
The show kicks off at 7.30pm tonight live on ITV1.
11 acts will battle it out to win the chance to perform in from of The Queen and win £500,000.
Click here for a profile of tonight's contestants.