The singer, who came second to Little Mix in the 2011 final, revealed that he is always in contact with the Take That star.
"Gary's like my dad now. I'd never dare disrespect him and I take everything he says on board because he's never wrong. He's not a man you want to disappoint," Collins told the Daily Mail.
"Everything is run by him - he knows exactly what he's doing. He's also co-written some of the songs. He emails and texts me all the time, and is constantly on the phone.
"He makes me laugh because if I can't answer for whatever reason, he'll leave a voicemail saying, 'Hello! It's Mr Barlow here and you're obviously too big now to pick up the phone!'"
Collins added that, although he is proud of his debut album, he feels "pressure" to succeed as "nothing's guaranteed".
> Marcus Collins spurns X Factor sob stories
Watch Marcus Collins in his video for 'Seven Nation Army' below: