All 5 members of One Direction have plenty of loyal fans, but the one name that tends to stand out as receiving the most attention is that of singer Harry Styles. Harry began as a solo artist - famously, 1D only came together after the members appeared separately on X Factor - and lately there have been rumours that he may be intending to go solo again. It is said that he has seemed less engaged with the band lately; for instance, at the 2014 Brit Awards he came on stage late claiming not to have heard the gong. He has also been spending a lot more time in the US lately - this may because he now has a girlfriend there, but as 1D are planning a tour this summer, it has been suggested that his being away so much could create difficulties.
You can read more about Harry Styles here.