I love his smile :)

Justin's smile is like Louis under my sunshine!

justin end niall beeeeeeeeeeeeeeeee

Justin Bieber has the best smile!!Belieber and Directioner forever

I hate to break it too you but in that pic niall is not smiling

I'm sorry, Niall but you're not really smiling so I can't choose you because the question was who got the best smile and as far as I can see on your picture. You are not smiling :O

+Amberla
Yes. Even though Niall is really very cute (and my die-hard celeb crush), I can't see him smiling in this pic but even JB is really good in his own way