Shane Filan says that Louis Walsh kept them on the straight and narrow during the Westlife days, saying he was "very strict".
The popstar explained that their former manager kept a close eye on them to make sure they didn't get into any trouble in their heyday.
Speaking to Digital Spy, Filan said: "We liked to have a drink but that was about it. We never did drugs, we didn't get involved in any mad, crazy sh** or anything like that.
"I think we were generally clean enough individuals anyway because our mums and dads would've f***ing killed us if we weren't. Louis [Walsh] was always very strict with us to a certain degree. He always reminded us how lucky we were.
"He'd be always watching everything. He had disciples out listening to us. It was crazy how much he knew about our lives outside work hours, but that's what a good manager does. He kept us together as a band, that's his job."
But did they have any vices? "We loved going out partying and having a drink. Vodka and Red Bull back in the day when that became a drink - Jesus! I drank too many vodka Red Bulls that's for sure."
Filan released his second solo album Right Here in September.