Songwriters Martin Harrington and Thomas Leonard, and bosses at their publishing company HaloSongs, are suing the star, alleging he copied elements of their 2009 single Amazing for the track, which became a 2010 hit for The X Factor winner Cardle.
Ed has yet to comment on the lawsuit, but Cardle insists he has no issues with the 25-year-old, while reminding fans and critics alike he didn't write the song at the centre of the drama, and is not named in the suit.
"Please read news articles closely," he writes on Twitter.com. "This is not my lawsuit. I think @edsheeran is a genius & 100% deserves all his success."
Harrington and Leonard are also seeking statutory damages and either an injunction or a running royalty.