The free music event, which takes place this year in Glasgow, Scotland, from May 23 to May 25, have managed to secure the boy band - made up of Harry Styles, Louis Tomlinson, Liam Payne and Zayn Malik - for the festival, despite them having another show on the same day in Dublin, Ireland.
The 'Little Things' hitmakers will also join Ed Sheeran, Kings of Leon, Coldplay, Tinie Tempah, John Newman, The Vamps and The 1975, who are all on the bill.
One Direction, who kicked off their 'Where We Are Tour' this month, which will see them play more than 60 dates across the world, will headline on the Friday night, with Coldplay topping the bill on Saturday and Kings Of Leon on Sunday.
In a statement, One Direction said: ''We're so excited to perform at Radio 1's Big Weekend in Glasgow. Glasgow we are coming to get you. We're going to put on a great show and we can't wait to see you all there.''
Kings of Leon drummer Nathan Followill also said: ''We're so excited to play Radio 1's Big Weekend. We've heard great things, and we can't wait to experience them first-hand.''
The 50,000 free tickets available for this year's event were snapped up in less than one hour and Ben Cooper, controller at Radio 1, described the line-up as ''phenomenal'', adding: ''It's probably the best in the world this year, in one of the world's great music cities.''