The Love Me Like You hitmakers believe they have to "work harder than most to earn people's respect" and will be up and about at three in the morning to get ready for a breakfast TV show before heading off to do interviews and a gig in the evening.
A source said: "The girls feel like they have to work harder than most to earn people's respect because they came from The X Factor and because they're a girlband. If they are doing breakfast TV they get there at 3am to be preened before going on screen at 7am.
"Then they'll go on and do interviews all day, radio promo and then a gig in the evening.
They are happy to work solidly and play the game. They get what they're here for and will do everything it takes to be the biggest girl group in the world."
Their busy schedule will no doubt come from their new "mass appeal" following the release of their third LP, Get Weird and the girls - Perrie Edwards, Jesy Nelson, Leigh-Anne Pinnock and Jade Thirlwall - have now set their sights on cracking America.
An insider added to The Sun newspaper: "Little Mix now have mass appeal. Kids love them, students love them and parents love them. They found an entirely new audience with their last album, Get Weird, and capitalised on it. Landing slots on the likes of Radio 2 and The Graham Norton Show was huge for them. Even men aren't ashamed to admit they are Little Mix fans now ...
"The girls want to get on and start recording their next record really soon. They have big aspirations to make a proper impact in America. There's a long way to go yet as far as Little Mix are concerned."