The department store John Lewis has denied copying a lo-fi arrangement of the song Together in Electric Dreams for use on their 2021 Christmas advert.
UK alt-folk duo The Portraits said the ad resembles the version of the Philip Oakey and Georgio Moroder hit which they released last year for charity.
The slow orchestral piano version featured their daughter on vocals.
Now the John Lewis rendition, which launched last week, is softly sung by 20-year-old Lola Young.
The group - aka Jeremy and Lorraine Millington from Wells, Somerset - wrote on Facebook that they contacted John Lewis in March 2021 to offer up the track for consideration for this year's ad but did not receive a reply.
They believe the new version is "borrowing the feeling and many elements of the arrangement" of their own - which was released to raise money for bereavement and mental health charities during lockdown.
John Lewis said in a statement to the BBC, which first appeared in The Guardian, that the duo did email a member of the marketing department but she left the company, adding that there is "no substance" to their claims.
It noted how there are other covers of the song in existence.
'No substance'
John Lewis responded by saying: "There's no substance to the claims as the person contacted by email left at the start of the summer and had no involvement in this year's Christmas ad.
"The music that accompanies the ad is always the final element to be added and this year was chosen at the end of October."
They added: "The creation of advertising and music is carried out solely by our agency and we are unable to read or consider ideas from other external or internal sources."