Ed Sheeran is being sued for $100 million.

The 27-year-old singer has been accused of copying Marvin Gaye's classic hit 'Let's Get It On' in his track 'Thinking Out Loud' and has been hit by a lawsuit from Structured Asset Sales (SAS), who own part of the copyright to the late singer's 1973 track.

According to legal documents filed in New York, the company believe Ed's 2014 single rips off the ''melody, rhythms, harmonies, drums, bass line, backing chorus, tempo, syncopation and looping'' of Marvin's song.

Other defendants listed in the claim include Sony/ATV Music Publishing, the Atlantic record label and Amy Padge, Ed's co-writer.

The 'Lego House' hitmaker previously faced legal action over the song from the heirs of Edward Townsend - who co-wrote the song with Marvin - but denied the allegations.

Last July, Ed reached an agreement to end a $20m copyright claim over his song 'Photograph'.

The chart-topping singer was sued by songwriters Thomas Leonard and Martin Harrington in June 2016, after they claimed his hit single had a strikingly similar structure to their track 'Amazing', which was released by Matt Cardle in 2012.

The songwriters argued in court that the tracks shared 39 identical notes, with similarities ''instantly recognisable to the ordinary observer''.

Papers were later filed dismissing the case with prejudice, with a California federal court set to enforce the terms of the settlement.

However, Richard Busch, who represented Harrington and Leonard during the case, refused to comment on the precise terms of the agreement.

But Matt Cardle has previously taken to Twitter to clarify he was not involved in the lawsuit and to express his admiration for Ed, hailing him a musical ''genius''.

Matt, who was the UK 'X Factor' winner in 2010, wrote: ''Please read news articles closely. This is not my lawsuit. I think Ed Sheeran is a genius and 100 percent deserves all his success.''

Meanwhile, in 2015, Robin Thicke and Pharrell Williams were ordered to pay $7.3 million in copyright infringement due to similarities between their number one single 'Blurred Lines' and Gaye's 'Got To Give It Up'.

However, both Robin and Pharrell denied any wrongdoing.

The payout was reduced on appeal, but the Marvin Gaye estate receives 50 percent of publishing and songwriting revenues from 'Blurred Lines'.