The 31-year-old singer had tried hard drugs before joining the band, and struggled with addiction after they split - but during his five month run in the group, the other members helped him stay clean.
He says, "Perhaps Take That saved my life.
"I'd have had a problem with drugs anyway. I was heading that way.
"In all seriousness I would have been a dealer or a burglar and that's the truth because I would not have had the money to fund my addiction and I'd have probably been in jail now.
"Before Take That I'd done acid, speed and smoked a lot of weed so I was sort of heading into that direction anyway.
"But for the other lads it wasn't really part of their life, other than we used to like to smoke weed and then giggle."