Canadian singer Avril Lavigne is facing a lawsuit by the members of a ‘70s rock band who are accusing her of stealing one of their tunes and using it for her hit song, "Girlfriend."

Songwriters Tommy Dunbar and James Gangwe of the Rubinoos, filed the suit in California’s Northern Federal District Court in San Francisco on July 2. The band claims Lavigne’s song bears striking similarities to their song "I Wanna Be Your Boyfriend," co-written by Dunbar and released by Beserkley Records in 1978.

Their lawyer Nicholas Carline accused Lavigne of making substantial copies of the song.

"She's made a lot of money off of my client's song,'' Carlin told the Canadian Press.

"The entire song is not the same, they have different bridges, but the heart and soul of her song is directly taken from our client's song.''

"We are not so naive as to chalk it up to some sort of cosmic coincidence," Dunbar said in a statement Thursday. "The lyric, the meter, the rhythm, they're identical."

The suit also cites Lavigne’s partner Dr. Luke and Avril Lavigne Publishing as responsible parts. Lavigne’s manager Terry McBride has hired an expert to compare the two songs, and has stated the two songs are different.

Regarding the case, entertainment lawyer Dave Steinberg told CTV’s Canada AM recently that "Copyright infringement is really about the melody and or the lyrics. And in this case I'm hearing some similarities between the two."

"There's definitely a similar look and feel between the two compositions. I don't know that there's enough there for copyright infringement however."

In response to the allegations, Lavigne's manager Terry McBride said the legal claims are "an unfortunate part of this business.'

"Avril's very, very sensible," McBride told the Canadian Press. "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.''

The first court date has been set for Aug. 28 in Oakland.