12 Controversial Songs That Were Stolen
5. 'Midnight Memories' - One Direction
Where It Was Stolen From: 'Pour Some Sugar On Me' - Def Leppard
Again, disclaimer needed: Def Leppard quite publicly stated that they have no intention of taking legal action against One Direction. Perhaps because of how odd hearing them and One Direction in the same sentence is?
The Sheffield rockers have all cited the universality of the chords used in their song, going as far as saying that if they sued 1D, then they'd get sued by whomever they "stole the song from."
That said, it's not unheard of for these things to be settled with a nice cheque and a non-disclosure agreement, so it may be that they can't say otherwise, but we should probably take their word for it.