Simon Cowell was reportedly furious when Gary Barlow was awarded an OBE (Order of the British Empire) by Queen Elizabeth earlier this year.
The Take That singer was given the prestigious title by Queen Elizabeth earlier this year but Simon - who Gary replaced as head judge on 'The X Factor' when the music mogul quit the UK show - was reportedly annoyed by Gary's success.
In a new chapter in Tom Bower's biography of Simon, 'Sweet Revenge', the author writes: ''The announcement that Barlow would receive an OBE for arranging the [Diamond Jubilee concert] added to his irritation. 'He chased that madly to get three initials after his name,' he carped.''
Simon was also said to be angry at ITV boss Peter Fincham for rehiring Gary for the show and often sent mean-spirited text messages about him to his friends.
The author added: ''The ambitions of Barlow, he believed, were comical. Ever since Barlow had clawed his way back after a disastrous attempt to become a solo star, Cowell was niggled by his conviction that Barlow was bidding to establish a rival entertainment empire and, like [Sir] Paul McCartney, secure a knighthood.
''He enjoyed snubbing the man who foolishly asserted that he was the top judge, not Louis Walsh, by texting his criticism about Barlow to others.''