Pop superstar Ed Sheeran is set to face off in court with the heirs of Marvin Gaye’s iconic soul single Let’s Get it On, who say one of Sheeran’s hits violates their copyright. 

The heirs of Ed Townsend, who co-wrote the 1973 soul classic, are suing Sheeran, alleging the English pop star’s hit 2014 tune Thinking Out Loud has “striking similarities” to Let’s Get It On and “overt common elements”.

The lawsuit filed in 2017 has finally made it to a trial that is expected to last a week in the Manhattan federal courtroom of 95-year-old judge Louis L Stanton.

Sheeran, 32, is among the witnesses expected to testify.

While the jury will hear the recordings of both songs, probably many times, their lyrics will be legally insignificant. The jurors are supposed to only consider the raw elements of melody, harmony and rhythm that make up the composition of Let’s Get It On, as documented on sheet music filed with the United States Patent and Trademark Office.

Sheeran’s lawyers have said the songs’ undeniable structural symmetry points only to the foundations of popular music.

“The two songs share versions of a similar and unprotectable chord progression that was freely available to all songwriters,” they said in a court filing.

Attorneys for Mr Townsend’s family point out in the lawsuit that artists including Boyz II Men have performed seamless mashups of the two songs, and that even Sheeran himself has segued into Let’s Get It On during live performances of Thinking Out Loud.

They sought to play a potentially damning YouTube video of one such Sheeran performance for the jury at trial, however the motion was denied. 

Judge Stanton said he would reconsider it after he saw other evidence that was presented.

Gaye’s estate is not involved in the case, though it will inevitably have echoes of its successful lawsuit against Robin Thicke, Pharrell Williams and T.I. over the resemblance of their 2013 hit Blurred Lines to Gaye’s 1977 track Got to Give it Up.