U.S. songwriters filed a lawsuit against the Canadian punk princess Avril Lavigne, claiming that her smash hit "Girlfriend" sounds suspiciously like the Rubinoos' tune, "I Wanna Be Your Boyfriend."

The Rubinoos, a bubblegum pop duo,  released "I Wanna Be Your Boyfriend" in 1979. It features the poppy chorus: "Hey, hey, you, you, I wanna be your boyfriend,'' lyrics similar to Lavigne's more up-tempo hit, which goes, "Hey, hey, you, you, I don't like your girlfriend.''

News of the lawsuit comes a day after Canadian artist Chantal Kreviazuk took a swipe at Lavigne's songwriting skills.

Kreviazuk and Lavigne worked together on songs in the past.

"Avril doesn't really sit and write songs by herself or anything,'' Kreviazuk told the American music magazine, "Performing Songwriter.''

Kreviazuk also told the magazine she sent a song called "Contagious" to Lavigne. A song with the same title appears on Lavigne's latest CD, with a credit to Lavigne and songwriter Evan Taubenfeld.

"Avril will also cross the ethical line, and no one says anything," says Kreviazuk. "That's why I'll never work with her again''

Lavigne's camp maintains the material is original and that any similarities to Kreviazuk's tune end with the title.

Terry McBride, Lavigne's manager and the CEO of Vancouver's Nettwerk Management Company, calls the controversial allegations nothing out of the ordinary.

"It's just, you know, typical music business," he told CTV's Newsnet.

"These types of suits are actually really, really common. It's unfortunate, but when you got a situation stateside where lawyers can work upon it on a contingency basis, people do fishing expeditions and that's what this is."

As for the two songs involved in this new lawsuit, McBride sees no similarities between them.

"Whenever we get one of these claims, the first thing that we do is send out to a musicologist who is an expert," he says.

Today's troubles for Lavigne, he says, will quickly pass.

Lavigne, 21, married fellow Canadian rocker Deryck Whibley of Sum 41 in 2006.

She recently released her latest album, "The Best Damn Thing," which has received mixed reviews.

Entertainment Weekly wrote: "The dumb, girly, giddy Best Damn Thing reembraces the 15-year-old pom-pom punkette within, with multitracked hand claps, Toni Basil-gone-bad cheers, and pep-rally-rattling guitars."

The album debuted at #1 in the U.S., Canada, Pakistan and Taiwan. It was certified Gold on the Taiwanese Albums Chart within three days of being released and later went platinum.

Born in Napanee, Ontario, Lavigne made her debut at the age of 16 with her first album, 2002's "Let Go." It sold millions, as did her follow-up, 2004's "Under My Skin." "Let's Go" snagged eight Grammy nominations and four Juno Awards, including Album of the Year and New Artist of the Year. "Under My Skin" unleashed smash singles like "Don't Tell Me" and "My Happy Ending" and scooped up three more Junos.

Lavigne claims to have written dozens of introspective songs on "Under My Skin." It was during that time that she and Kreviazuk developed a close bond. A lunch meeting one day turned into a major chick-bonding session says Lavigne.

Later, a one-night writing session spawned a two-week collaboration between the two women. Lavinge moved shortly into the Malibu home owned by Kreviazuk and husband Raine Maida so they could record together.

Lavigne says she was involved in every aspect of the making of that record.

While McBride calls the lawsuit against his client baseless, he admits they may have to settle out of court. Pointing to the 1999 lawsuit against singer Sarah McLachlan, which the Canadian artist ultimately won, McBride says the costs of defending a case can prove too high.