Amd Whah has an interesting blog called Any Major Dude With Half a Heart with lots of musings on music. Here's an example of one of his "copycat" genre of posts:
William Bell – I Forgot To Be Your Lover (1971)
Billy Idol – To Be A Lover (1986)
Van Morrison – Have I Told You Lately (1989)
When Van Morrison wrote Have I Told You Lately, most interpreted the song as a love song to God. Van's spirituality was vaguely Christian and Christians really want to believe that those who have been given much in this world are, at least, a little grateful. Four years later, Rod Stewart donned his tight, unnatural fibres thing and turned the song into the syrupy creation it now is. It's ever to be found alongside songs like I just Called to Say I Love You on Love Song Compilations churned out each Mother's Day.
Have I Told You Lately is utterly gorgeous, and very much a Van Morrison song, and therefore best heard in the version by one of the greatest songwriters of any generation. So I feel almost sorry to point out that the very line that gives the song its title is almost identical to the opening line of William Bell’s I Forgot To Be Your Lover, in melody and lyrics.
Far be it for me to accuse Morrison of plagiarism, or even deliberately copying somebody else’s melody. Morrison could even plausibly claim never to have heard the William Bell and Booker T Jones composition, which was a hit for Bell in 1968 and then was re-recorded for the soul singer’s 1971 album Wow… (it’s the slightly longer 1971 version featured here, because it is the more uncanny-sounding one).
Perhaps Van Morrison, a soul fan who described himself as a soul singer, heard it and forgot about it. Maybe it resided in the deeper recesses of his subconscious playlist, a forgotten but not erased memory, jogged perhaps by Billy Idol’s 1986 cover of I Forgot To Be Your Lover, then retitled To Be A Lover (though Idol probably covered the George Faith version of 1977). Whatever the case, the similarity of the opening of Bell’s song and that of Morrison’s is striking.