Pete Waterman thinks Simon Cowell knows "very little" about music.
The '80s record producer referred to the 'The X Factor' boss as a money making machine with no interest in real talent.
The 68-year-old told Daily Mail's Event magazine: "Simon knows very little about music. His knowledge comes out of the 'Guinness Book of
Hits'. He'd keep a copy on his desk, and whenever an act came in he'd skim it for an old number one, look at the sales figures and then do it again. I love Simon he's the smartest man I know, but he isn't in it for the music."
He also criticised One Direction - who the music mogul manages - calling them "the greatest marketing phenomenon ever".
He told the British magazine: "One Direction is a band but it sure as hell ain't anything to do with music. They are the greatest marketing phenomenon ever. Go and see one of their concerts - they are an eye-opener. It's all about sending tweets and talking to the crowd.
“You don't come out humming the tunes. All One Direction do is prove that Simon Cowell is a genius when it comes to making money. They are worth millions."
The former 'Pop Idol' judge added: "But imagine for a moment if they really could sing, really did write great songs - they would be worth squillions."