The electro-funk band Collage, who Mars and Ronson have said influenced the creation of the track, filed a lawsuit accusing the pop duo of "deliberately and clearly" copying their song "Young Girls."
In 2014, the funk band Sequence accused Mars and Ronson of copying their 1979 song "Funk You Up," but a lawsuit was never filed.
The Gap Band received songwriting credits in 2015 from Mars and Ronson after alleging the chorus to "Uptown Funk" was identical to the chorus of their track "Oops! Upside Your Head." Three members of the Gap Band, and two other members of their band, were given writing credits on the song as a result of the accusation.
The lawsuit from Collage, however, alleges more than similarity, arguing the song is basically a copy of theirs in many instances.
"Upon information and belief, many of the main instrumental attributes and themes of 'Uptown Funk' are deliberately and clearly copied from 'Young Girls,'" the band alleges in the filing, "including, but not limited to, the distinct funky specifically noted and timed consistent guitar riffs present throughout the compositions, virtually if not identical bass notes and sequence, rhythm, structure, crescendo of horns and synthesizers rendering the compositions almost indistinguishable if played over each other and strikingly similar if played in consecutively."
The suit was filed by the estates of two deceased members of the band, Grady Wilkins and Lee Peters, and the lone living member of the band, Larry White. In addition to Mars and Ronson, White and the estates name other writers on the song and three record labels linked to the track.
Collage seeks unspecified damages and profits for the alleged infringement, and any payout from the case could be sizeable based on the success of "Uptown Funk." The track is the biggest hit of Mars' career, having sold more than 6.1 million copies and netting about $100,000 per week for streaming on Spotify.