The track - released on November 12 - is the second to be taken from their new album Take Me Home, the follow up to 2011's Up All Night.
'Little Things' was written by Ed Sheeran, who confirmed that he was working with the five-piece earlier this year.
Sheeran revealed that he had written two songs due to appear on the band's album and that both were about his ex-girlfriend.
"One of them is kind of a getting-back-together song. One of them is an appreciation song," he said.
One Direction have also unveiled five Take Me Home limited edition box-set covers that feature the individual members of the group. Fans who pre-order the bundle will also receive a One Direction T-shirt, bracelet and sticker sheet.
The band are scheduled to take over a slot on Capital FM next weekend (October 26 to October 28) as part of the station's Help a Capital Child appeal. Other acts that have been lined up to present spots include fellow X Factor stars Little Mix and JLS.