The book hit headlines last month with its revelations about Cowell's private life, revealing an affair with his former X Factor colleague Dannii Minogue, along with further claims about his relationship with ex-fiancée Mezhgan Hussainy and suggestions that he was "mesmerised" by Cheryl Cole.
> Amanda Holden: 'I'd never be another notch on Simon Cowell's bedpost'
David Walliams told victorious semi-finalists Ashleigh and Pudsey after their performance: "Thank you for making my Simon so happy. He has had a difficult few weeks and this has cheered him up."
Walliams had started the show by reading Bower's unauthorised biography, claiming "I can't put it down".
Amanda Holden also told Cowell that "we don't need a third volume of the book" in response to his comments about attractive backing dancers on the programme, while Cowell himself joked: "I've had a lot of dogs in my life, but never one like this" after Ashleigh and Pudsey's semi-final performance.
Bower's book additionally claims that Cowell prefers black toilet paper, spends £3,000 per year on flowers and that he described Gary Barlow's X Factor judging performances as "too scripted" and "a bit stiff".
Britain's Got Talent's live semi-finals continue tonight (Monday, May 7) at 7.30pm on ITV1.