Niall Horan prefers to be "casual" on the red carpet

The group's stylist, Caroline Watson, said: "That's his personal preference. We make it as dressed-up as we can, but in a casual way so he feels comfortable and photographs well.

"Plus, it's good for him to be a bit different from the others."

However, the 21-year-old singer is keen to smarten up his image in subtle ways, though he doesn't want to look "too over the top".

Caroline added to heat magazine: "He's getting older and wants to be smarter about certain things.

"We did the BBC Music Awards in December and he wore skinny jeans and boots with a smart jacket and shirt.

"Still relaxed, and not too over the top."

Perhaps Niall, 21, is smartening up his image because of the new lady in his life.

It was reported last month that the 'Best Song Ever' star was spotted cuddling up to a pretty brunette named Melissa Anne, also 21, in Melbourne.

One heartbroken fan, Vanessa, tweeted: "OMG Niall Horan and Melissa. They were seen in a casino, they kissed. And he held her by the waist and playing with her hair (sic)."

While Iena, wrote: "melissa was a fan and now here she is making out and hooking up with niall horan how did she do it (sic)."

And another fan, who goes by the user BibiHoran, added: "The moment when i heard about @NiallOfficial and melissa i was shocked, happy for him and really sad at the same time #mixedfeelings (sic)."