Fans have been quick to point out the similarities between Katy Perry’s latest single Roar and Sara Bareilles' recent release Brave. Both parties are currently keeping quiet, although Perry has previously tweeted her admiration for Bareilles' song. Coincidence, copy or flattery? Judge for yourself...

It goes without saying that naturally two songs are going to sound similar from time to time, more often than not completely accidentally. It’s very much within the realm of probability that two artists will independently stumble across the same chord progression. Sometimes, though, the similarities are a little too pronounced, and we have to reconsider that fine line between imitation and flattery...

Well-known artists such as The Beach Boys, Johnny Cash and Oasis have all been on the wrong side of plagiarism rulings, whereas suits against the likes of Coldplay, Andrew Lloyd Webber and the Bee Gees have proven unsuccessful.

A curious case earlier this year saw singer/songwriter Jonathan Coulton - best known for his songs from the Portal videogames - accuse Glee of plagiarism. What made it particularly interesting was the song in question was a cover version, specifically of Sir Mix-a-Lot’s Baby Got Back.

Coulton’s argument was that Glee had borrowed, without permission, his own arrangement of the song, right down to vocal and background track quirks (including the rather telltale extra reference to a ‘Johnny C’). On uneasy legal ground, Coulton opted to re-release his cover (now ‘in the style of Glee’) as a single, and donate all proceeds of the 'cover of a cover of a cover' sales to charity for a year. Here’s the two versions layered on top of each other:

Ray Parker Jr’s Ghostbusters theme might be one of the most iconic film themes of all time, but did you know it was the subject of a lengthy legal battle after Huey Lewis argued it was an infringement of his band’s song I Want a New Drug? The parties ultimately reached an out-of-court agreement. As a curious aside, it has been reported that Huey Lewis was originally approached to write the Ghostbusters theme himself, but declined to focus on Back to the Future instead.

Such cases don’t always wind up as nasty disagreements, though. Very strong similarities were noted between Bruce Springsteen’s Radio Nowhere and Tommy Tutone’s Jenny (867-5309). Lead singer Tommy Heath has said he’s flattered by the similarity. He declined the opportunity for legal action, instead reflecting that “there’s too much suing” in this world of ours. Awh.