Thicke, Pharrell Williams and Clifford Harris Jr. claim they were threatened by both Gaye's family and Funkadelic's rights owner, who each asserted that the summer hit wasn't original.

In order to shield "Blurred Lines," the hottest hit of the summer, Robin Thicke, Pharrell Williams and Clifford Harris Jr. are going to court.

A lawsuit was filed Thursday in California federal court by the trio against Marvin Gaye's family and Bridgeport Music, which owns some of Funkadelic's compositions. At issue are complaints about similarities between "Blurred Lines" and at least two songs.

According to the suit, a copy of which was obtained by The Hollywood Reporter, "Plaintiffs, who have the utmost respect for and admiration of Marvin Gaye, Funkadelic and their musical legacies, reluctantly file this action in the face of multiple adverse claims from alleged successors in interest to those artists. Defendants continue to insist that plaintiffs' massively successful composition, 'Blurred Lines,' copies 'their' compositions."

Read the lawsuit here.

The suit claims the Gaye family is alleging that "Blurred Lines" and Gaye's "Got to Give It Up" "feel" or "sound" the same, and that the "Gaye defendants are claiming ownership of an entire genre, as opposed to a specific work."

As for Funkadelic, there's said to be claimed similarity between Thicke's hit and Funakedlic's "Sexy Ways."

"But there are no similarities between plaintiffs' composition and those the claimants allege they own, other than commonplace musical elements," states the lawsuit. "Plaintiffs created a hit and did it without copying anyone else's composition."

A New York Times critic has noted that "Blurred Lines" is "influenced heavily" by Gaye’s “Got to Give It Up,” but the lawsuit makes the point that "being reminiscent of a 'sound' is not copyright infringement. The intent in producing 'Blurred Lines' was to evoke an era."

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The Gayes and Bridgeport are said to be threatening litigation should the plaintiffs not pay a monetary settlement. Rather than wait for such a lawsuit to proceed, the plaintiffs are going to court to determine the parties' respective rights and obligations.

In seeking a judgment, Thicke, Williams and Harris Jr. are not only looking for a declaration that their song doesn't violate the defendants' rights by copying their songs, but also that the "Gayes do not have an interest in the copyright to the composition 'Got to Give It Up' sufficient to confer standing on them to pursue claims of infringement of that composition."

The plaintiffs are represented by Howard King and Stephen Rothschild of King Holmes Paterno & Berliner.

THR has reached out to the defendants for comment and will update with a response.

UPDATE: George Clinton, who once led Funkadelic and has feuded with Bridgeport and its leader over the years, tweets, "No sample of 's 'Sexy Ways' in @ 's 'Blurred Lines' - yet Armen Boladian thinks so? We support @ @ !"

E-mail: Eriq.Gardner@THR.com

Twitter: @eriqgardner