Simon Cowell has quit smoking cigarettes.

The 'X Factor' boss has finally kicked his 40-a-day habit in a bid to preserve his looks by taking up electronic cigarettes, which let him get his nicotine hit without having to inhale harmful smoke

Amanda Holden, his fellow 'Britain's Got Talent' judge, told The Daily Mirror newspaper: ''Simon does not smoke anymore. He has got a vaporising cigarette instead. He smokes air, or rather water. It's amazing.''

A 'BGT' source added: ''Simon is trying to cut down on the menthols and he's finding that electronic cigarettes are really helping.''

The 53-year-old star has his work cut out for him, having tried to quit twice before without success.

In January 2012, Simon underwent hypnotherapy in a desperate attempt to give up the habit, and managed to cut down from 44 cigarettes a day to 15 with the support of his friends and family.

He was then ordered to stop altogether by his doctor when he collapsed from nervous exhaustion last summer.

Simon - who has a history of lung cancer in his family - previously admitted he started smoking at the age of eight when his brother offered him a cigarette.

The star might be famed for his health-conscious lifestyle and following fads like sheep placenta facials and inhaling pure oxygen from a gas can, but he hasn't been able to banish his favourite vice.

He confessed: ''I genuinely still love smoking. I equate smoking with having a good time.

''I shouldn't be saying this but, well, they're not illegal, are they? After sex - amazing.''