More than 200 musicians are backing Pharrell Williams, Robin Thicke and TI in their legal fight over the hit song Blurred Lines.
Lawyers for the trio have appealed against a copyright infringement ruling last year, which saw them ordered to pay Marvin Gaye's descendants £5.6m ($7.4m) - later reduced to £4m ($5.3m).
The soul legend's children had sued, claiming the biggest song of 2013 copied Gaye's 1977 hit Got To Give It Up.
Now 212 musicians, including composer Hans Zimmer, R Kelly, and members of Linkin Park, The Black Crowes and Three 6 Mafia have filed a brief with the Ninth Circuit Court of Appeals expressing concern about the ruling.
The musicians say the ruling could have "adverse impact on their own creativity, on the creativity of future artists, and on the music industry in general".
The group - which also includes members of Weezer, Tears For Fears and Fall Out Boy - goes on to say that the two songs "do not have similar melodies; (they) do not even share a single melodic phrase" and contends that the similarity is about "feel" and "groove".
The brief also notes that Marvin Gaye was heavily influenced by artists including Frank Sinatra, Smokey Robinson, Nat 'King' Cole and James Brown.
Thicke and Williams' appeal contends that the judge presiding over a week-long trial last year gave jurors a number of improper instructions.
They say judge John Kronstadt misread the law by allowing comparisons of recordings of the two songs, rather than just the sheet music.