Rapper 50 Cent is being sued by the ex-frontman of rap group 2 Live Crew for allegedly stealing a line for his 2003 hit single In Da Club.
50 Cent won six prizes at December's Billboard Awards
Luther Campbell filed a claim at Miami Federal Court that 50 Cent used the opening line of Campbell's song It's Your Birthday, changing just one word.
Campbell's lawyer said that in In Da Club, "Sheila" becomes "shorty" in the line "Go shorty, it's your birthday."
50 Cent, whose real name is Curtis Jackson, was unavailable for comment.
Campbell's song appeared on his 1994 solo album Still a Freak for Life.
The claim was filed on behalf of Lil' Joe Wein Music, which holds the copyright for It's Your Birthday.
Campbell's lawyer Richard C Wolfe said: "It's the melody, it's the pace, the style - everything about that one line is the same."
"We're entitled to a portion of the profits."
The case also claims that Campbell's song I Like It, I love It can also be heard on the 2003 DVD 50 Cent - The New Breed.
Campbell is seeking unspecified damages in addition to lawyers' fees and other legal costs.
Wolfe won a $2.3m (£1.2m) judgment against Campbell in 1994 for another rapper who claimed Campbell withheld royalties.