As the fresh new face of rock music, singer-songwriter Avril Lavigne stormed to the top of charts with a seemingly original blend of racy tunes and cutting-edge lyrics. But now there are claims that her success might not be entirely down to her own hard work.
A lawsuit filed in a California court by an obscure 1970s pop band alleges that the 22-year-old Canadian stole one of their songs and reworked it into her recent bestselling single Girlfriend.
"The lyric, the metre, the rhythm, they're identical," said Tommy Dunbar, guitarist and lead songwriter of the Rubinoos, whose most famous accomplishment was providing the music for the film Revenge of the Nerds.
"We are not so naive as to chalk it up to some sort of cosmic coincidence."
Mr Dunbar is so certain that Lavigne's recording is a rip-off of the Rubinoos' 1979 single I Wanna Be Your Boyfriend that he has posted links to performances of both songs on his band's website, inviting fans to make up their own minds.
The chorus of his song contains the words: "Hey, hey, you, you I wanna be your boyfriend," while Lavigne sings: "Hey, hey, you, you, I want to be your girlfriend" in a remarkably similar style. Girlfriend reached the top of the American singles chart and number two in the UK.
Terry McBride, Lavigne's manager, dismissed the plagiarism claim as "an unfortunate part of the business".
"Avril's very, very sensible," he told the Canadian Press agency. "She knows music well. If the chords had been similar, the melodies had been similar, lyrics had been similar, she would have gone, 'OK, I can see their point'. But nothing's similar."
Mr McBride said he asked a musicologist to compare the two songs when the allegation first arose, and said "this one came back so solidly on our side it's just ridiculous".
Yet music industry experts say the Rubinoos might have a case. Stephen Thomas Erlewine, a writer for Billboard magazine, said Lavigne's version appeared to be "a total lift" from the earlier song.
Entertainment lawyer Dave Steinberg, meanwhile, told Canadian TV station CTV he was surprised that Mr McBride was offering to settle the case out of court in exchange for costs.
"If I were representing her, I'd be saying my client has a massive amount of credibility and legitimacy as a songwriter," he said.
"She does not steal and anybody who wants to sue us can come and try to take a shot and we will defend it vigorously."