One Direction's Niall Horan has posted a "before and after" picture on his Twitter account after having his braces removed.

The Irish heartthrob took to the social networking site this morning to let fans know he was taking a trip to the dentist's surgery today.

“Morning. ! This is it ! I'm goin to the dentist! I think this is my last hour with braces! Oh how I'm gona miss them ! Naaaaaaat ! (sic)."

Horan then proudly posted a picture of the results on his page, accompanied by the caption: "Before and after!"

After having his braces fitted in December 2011, Horan has been on a countdown to having them removed.

Earlier this year he tweeted: “Goodmorning lovers! just t let ya know ..as i always get asked…the braces are coming off 3rd of april forever! (sic)."

Meanwhile, the director behind One Direction's 3D movie '1D: This Is Us' has revealed some behind-the-scenes secrets about the five-piece.

He teased on Twitter that the lads had been warned off eating burgers in a bid to keep in shape for their string of tour dates.

He wrote: "They love eating McD in front of me, but on the new tour they have a trainer who's keeping them off the Big Macs! (sic)."

He added: "We spend a lot of down time w/ the band, w/ their families and friends. We really wanted you to see what their "normal" lives are like. One of the things I really love about the lads is how much they care about and support each other. They really stand by one another (sic)."