Simon Cowell has learned to look after himself more since becoming a father.

The 'X Factor' boss used to be infamous for his unusual sleeping habits but his friend Dermot O'Leary says he keeps to more regular hours and doesn't work as much now he has three-year-old son Eric - whose mother is Simon's girlfriend Lauren Silverman - to look after.

Dermot said: ''Eric's definitely helped and I think he's changed.

''He sleeps better now. With living half your life in America and half over here, it's quite hard to have regular sleepnig patterns and he notoriously goes to bed really late, but at Judges' Houses he went to bed early.

''Someone was like, 'Shall we ask Simon?' and someone else said, 'He's gone to bed!'. And we were like, 'It's 11 o'clock!'

''I'd never say Simon would take it easy but he definitely thought about it and he's being as healthy as he can.' ''

Simon missed one of the 'X Factor' live shows last year after falling down the stairs at home, and when he returned to work, Dermot, 44, and the programme's other judges, Louis Walsh, Sharon Osbourne and Nicole Scherzinger, couldn't resist poking fun at the 58-year-old music mogul.

Dermot admitted to Britain's OK! magazine: It's always hard when something like that happens to one of your friends, as you want to make sure they're alright.

''As soon as you know they're alright, it's the British way to mercilessly take the p**s out of them as much as you possibly can.

''As soon as we knew Simon was OK, the gloves were off with jokes like, 'Simon's favourite band used to be Steps but he can't listen to them any more.'

''He was fair game with it all and there's no way he wouldn't give it to any of us if it happened to us. That's why he's a good boss.''