A song that was written by Bruce Springsteen for 2001 movie Harry Potter and the Philosopher's Stone leaked online, Friday, after being included as part of a bootleg compilation.

Springsteen first mentioned he had written a song that didn't end up being used in the movie in an interview with BBC Radio 2's Simon Mayo in October, and since then fans have been eagerly waiting to hear it. However, the mysterious track was later removed from Soundcloud, where it had first surfaced.

Bruce SpringsteenBruce Springsteen’s unused Harry Potter ballad, ‘I'll Stand By You Always’, has surfaced online

The song, titled ‘I'll Stand By You Always’, is described by Rolling Stone as ‘earnest and unhurried, with a soft, sweet gospel hook’, but perhaps ‘a little too somber,’ for the children’s film.

The track is also said to contain no references to characters or specific plot points from J.K. Rowling's books. Lyrics include: "Together we'll chase those thieves that won't leave you alone/ Out from the under the bed, out from over our home." 

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Speaking about the track in October, The Boss described it as "pretty good,” adding: “It was a song that I wrote for my eldest son, it was a big ballad that was very uncharacteristic of something I’d sing myself.”

Springsteen didn't give a reason as to why it didn't make it on the film’s soundtrack but did add: “At some point I'd like to get it into a children's movie of some sort because it was a pretty lovely song.”