When British boy band One Direction released their latest album, Midnight Memories, some noted that the title track sounded like Def Leppard's Pour Some Sugar On Me.

Now, sources tell British tabloid The Mirror that Def Leppard's lawyers are looking to see if the British rock band has a case against the British boy band.

The source tells The Mirror, "Music lawyers will routinely scour hits like this one to see if there is any evidence that a band has either copied or cleverly mimicked a Def Leppard song...Everyone is staying silent at this stage but it’s clear the two songs sound alike – which has been enough for Def Leppard’s aides to pose questions to their legal team.”

This isn't the first time a One Direction song was thought to have a remarkably similar sound to a British classic rock song.  Their hit, Best Song Ever, drew comparisons to The Who's Baba O'Riley.
There was a rumor that The Who would sue.  They did not.