The 26-year-old singer tragically lost his mum Johannah Deakin in 2016 when she passed away aged 43 after losing her battle with leukaemia, and the One Direction star admits he is ''really lucky'' to be able to turn to the music mogul in such tough times.
Louis said: ''He's one of the people I take advice from and speak to in those moments. I'm really lucky I've got such a good relationship with Simon.''
But the 'Little Things' hitmaker admits he must have been a ''pain in the a**e'' for Simon during the first 18 months of knowing him when One Direction were formed.
He is quoted by The Sun's Bizarre TV column as saying: ''I don't like to stick to the rules and neither does Simon, so for the first 18 months after meeting I must have been a pain in the a**e.''
One Direction took an indefinite hiatus in 2016, six years after Simon put the band together on 'The X Factor' - on which he and Louis are now judges - and the 58-year-old star recently predicted the boy band will reunite one day.
He said: ''I just think the legacy is too big not to go back to at one point. Plus they have enough songs. I didn't realize how many hits they've had... When they do get back together it will be a huge event.
''But look, they're all doing their own thing and they're all being successful. But I have a feeling it will happen. I really do. I'd love it to happen.
''Individually they were all great. The group was the launchpad, but, of course, everyone would love to see them back together -- even if it was just a series of concerts.''
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