The 23-year-old singer was previously ordered to pay the songwriter royalties because of similarities between the track and his own song 'Stay With Me', but he insists it is just an unfortunate coincidence because he had never even heard the 1989 composition.
He told GQ magazine: ''It's never going to be fair to me because I sat in a room with two guys and wrote a song.
''One guy played some beautiful chords and I started singing and wrote a song about a one-night stand. That is genuinely how it was.
''I am 23 years old - Tom Petty's song came out way before I was born and still to this day - people don't know this - I actually haven't listened to the song.
''I refuse to listen to it. Even now I won't listen to it.''
Sam insists it was just an ''unfortunate'' mistake, and though Tom was gracious about the row, he will never agree with the ruling.
He added: ''There are only so many notes on a piano... We were just unfortunate that it happened, but there was no bad intention.
''Tom Petty wrote me a really nice letter, which I thought was really kind, but I am never going to be happy about it as it's still my song to me.''
Tom has previously described the similarities between the two songs as a ''musical accident'' and insisted he bears no ill-will towards Sam.
He wrote on his official website: ''About the Sam Smith thing. Let me say I have never had any hard feelings toward Sam. All my years of songwriting have shown me these things can happen. Most times you catch it before it gets out the studio door but in this case it got by.
''Sam's people were very understanding of our predicament and we easily came to an agreement. The word lawsuit was never even said and was never my intention. And no more was to be said about it.
''How it got out to the press is beyond Sam or myself. Sam did the right thing and I have thought no more about this. A musical accident no more no less. In these times we live in this is hardly news.
''I wish Sam all the best for his ongoing career. Peace and love to all.''
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