The official song, also called Skyfall, was scheduled to premiere on the singer's website at 0.07am (Gmt) on Friday (05Oct12), which has been declared Global James Bond Day.
However, fans managed to hear a preview of the tune on Tuesday (02Oct12) after it emerged on free streaming site Soundcloud and YouTube.com.
Bond lovers have been enthusiastic about the track, with former Spandau Ballet star Martin Kemp writing in a post on Twitter.com, "Adele's Bond song is superb, it has everything a 007 movie theme song should have... Hats off to you!"
Paul Epworth, who wrote the track with Adele, addressed the leak on Twitter.com and urged fans to wait until Friday to hear the proper version, writing in a post, "I hear a short excerpt of Skyfall leaked... I can't wait for everyone to hear the whole thing because Adele's performance is jaw dropping."
Adele recorded Skyfall at London's famed Abbey Road Studios accompanied by a 77-piece orchestra.