Dressed in a dark suit and tie, the entertainer appeared in person at the High Court in London on the first day of the trial, which is scheduled to last three weeks.
He is accused by Sami Chokri and Ross O'Donoghue of being partly inspired by their title "Oh Why" for the melody of his planetary hit "Shape Of You", the best-selling title in the world in 2017.
Both songs were played on Friday in the courtroom presided over by Judge Antony Zacaroli.
For the plaintiffs' lawyer, Andrew Sutcliffe, "the similarity" between certain passages "is striking", they are "almost identical".
"Mr. Sheeran is undoubtedly very talented, he is a genius. But he is also a magpie," he added, referring to the bird which is sometimes accused of being a thief.
"He borrows ideas and throws them into his songs, sometimes he acknowledges it, sometimes he doesn't", he continued: it "depends on who you are and if he thinks he can do it with impunity" .
The lawyer pointed out that his clients are "very talented songwriters, who deserve the same respect as any other artist and recognition when it is due".
Ed Sheeran and his co-authors, Steven McCutcheon and John McDaid denied these accusations.
They had applied in May 2018 to the High Court for it to recognize that there had been no copyright infringement.
Two months later, in July, Chokri and O'Donoghue in turn began legal proceedings against them.
The payment of royalties linked to "Shape Of You", estimated at 20 million pounds sterling (24 million euros at the current rate) according to the newspaper The Telegraph, has been suspended by the collective management organization PRS.
In 2017, Ed Sheeran was also the best-selling artist in the world, according to the International Federation of the Phonographic Industry (IFPI), with his third album "Divide" which includes the single "Shape Of You ".
© 2022 AFP