With the aid of prosthetics and a huge team of make-up artists, Niall looks more like Lord Alan Sugar than the Irish popstar we all know and love!
The singer has magically sprouted a greying beard and receding hairline, along with a fair few wrinkles on that young forehead of his.
Chatting on the phone in a business suit, Niall doesn't look very impressed either!
The actual premise for the video remains a secret, but it has been confirmed that all five band members - Niall, Harry Styles, Louis Tomlinson, Liam Payne and Zayn Malik - will take on different characters in the footage, although not all will wear prosthetics.
Niall's new look is first to be revealed and over the course of the next four days, the rest of the lads' transformations will be unveiled.
'Best Song Ever' is the first song to be taken from One Direction's next album and is available to download from 22 July.
Check out the trailer for 1D's film This Is Us and tell us what you think, as the best comment from across the website each week wins £50!