The One Direction heartthrobs will premiere their brand new debut movie, 'This Is Us', in London's Leicester Square later this evening (August 20) and the guys have thanked their fans for getting them to where they are today.

Singer Niall Horan took to his official Twitter page ahead of tonight's event and told his 13.4 million fans that they are the ones to thank for being able to enjoy such phenomenal success around the world:

"Just want to say! Drove into the city last night! And went near Leicester square, and there was soo many people camping! Wow thank you! Just pinching myself! Absolutely huge day today! We want u to know that u made this all happen!"

He added: "And when u see the film or are standing on Leicester square tonight, u can all turn to each other and be like, "we did this" so thank you so much. I'm definitely wearing nappies tonight, I'm that excited!"