One Direction's Irish heartthrob Niall Horan has reached an exciting milestone on social networking site Twitter today (August 5).

The 'Best Song Ever' superstar took to his page on the site and told his fans: "Wow! 13 million followers! U guys are amazing! Welcome to my world anyone who has just joined us here!! It can be quite random at times."

The only other member of the boyband to be ahead in terms of followers is Harry Styles, who currently has 14.8 million, as singer Liam Payne and Louis Tomlinson both have 11.8 million, and Zayn Malik is behind with 9.7 million.

Meanwhile, the lads are gearing up for 4 concerts at the Staples Center in Los Angeles (August 7-10) and Horan explained that it's an overwhelming prospect: "All very quiet on the bus tonight! Think everyone is tired! Need to rest up and be ready! For 4 staples shows, can't believe I just said that."