Robin Thicke is being sued for copyright infringement over his hit song "Blurred Lines."

Marvin Gaye's children have filed legal papers accusing the singer and Pharrell Williams, who features on the track, of copying elements of the song "Got To Give It Up," according to The Hollywood Reporter. They are seeking damages and a portion of the profits from the song, which has been one of the biggest hits of 2013.

The lawsuit is in response to a claim brought in August by Robin and Pharrell, asking a court to rule their song did not infringe Marvin's copyright. In their legal papers - also filed on behalf of fellow collaborator T.I. (Clifford Harris, Jr.) - the trio insisted there were no similarities between the two songs "other than commonplace musical elements."

In the lawsuit, Frankie and Nona Gaye, Marvin's children, allege that Robin more or less admitted to plagiarizing their late father's work in interviews. They also said his 2011 song "Love After War" amounted to "unlawful copying" of Marvin's 1976 track "After The Dance War."

The legal claim argues that record label EMI should have protected Marvin's musical legacy by pursuing a copyright infringement claim, but instead allowed a conflict of interest to arise between the family's rights and the profits it is earning from "Blurred Lines" sales. "This conflict has resulted in EMI's intentional decision to align themselves with the ["Blurred Lines"] writers, without regard to the harm inflicted upon the rights and interests of the Gaye Family, and the legacy of Marvin Gaye," the court documents stated.

Sony/ATV Music Publishing, which owns EMI, said it took its role of protecting its songwriters' works from infringement very seriously. "While we have not yet seen the claims by the Gaye family against EMI, we have repeatedly advised the Gaye family's attorney that the two songs in question have been evaluated by a leading musicologist who concluded that 'Blurred Lines' does not infringe 'Got To Give It Up,'" the company said.

Sony/ATV also said while it treasured the work of the late singer and the company's relationship with his family, "we regret that they have been ill-advised in this matter."