The Irish star was spotted wearing a cast on his right foot during the group's gig in Montreal, Canada, but he has no idea how he got injured, reported Daily Mirror.
Asked about the obvious injury onstage by bandmate Louis Tomlinson, the 21-year-old said, "I woke up before the show the other day and I had a pain in my foot. Then I went to get an X-ray today and I've got a fractured right foot and I don't know how."