Pop artists have shaped fashion for decades: Think of David Bowie’s androgynous Ziggy Stardust persona in the ‘70s, Madonna’s nod to bustiers and lingerie-as-outwear in the ‘80s and Nirvana’s grunge-rock plaid-shirts in the ‘90s. Their style statements had a huge impact on youth and this trend continues today. Take Avril Lavigne. 10 years ago – wearing neckties as part of her style – thousands of young girls copied the look. Today, the Canadian singer, whose album sales have surpassed 30 million worldwide, has her own fashion line, Abbey Dawn, which she launched in 2008 and is now expanding and upgrading. She just showed off the new collection in New York City Fashion Week at Style-360 Metropolitan Pavilion.

“I had an Abbey Dawn fashion show and it was the second time I’ve been in Fashion Week in New York,” 27-year-old Lavigne tells ELLE Canada. “The brand is coming out in spring as a full collection for the first time with eight categories. There’s men’s clothing, footwear, eyewear, swimwear, bags and it’s also going internationally.

“The web site is up — AbbeyDawn.com — but it just has a mini collection up there at the moment, but the full collection’s coming out in spring, 2012. So it’s going to be the biggest it’s been. It’s also better quality. It’s very formal. When I first launched Abbey Dawn, the clothes were way cheaper. The clothes are much better now.”

A few weeks ago, the web site had a big end-of-summer blowout sale and now it is showcasing new tops, dresses and mainstays of her line. The new upgraded collection won’t be online until January, she says.

One of the items she has been selling on AbbeyDawn.com is a charity T-shirt in aid of the on-going recovery efforts for the victims of the March earthquake and tsunami in Japan. “We made a T-shirt with Abbey Dawn that says ‘I love Japan,’” says Lavigne. “The proceeds go to the victims, the younger kids and families affected by the disaster over there.” The black T-shirts have a big red heart, the brand name at the top, and “Japan” at the bottom. It ends up reading: Abbey Dawn ♥ Japan.

100% of the net proceeds from the shirt go to The Avril Lavigne Foundation to support Mercy Corps’ Comfort for Kids program.

A year ago, Lavigne started her foundation and is working with Global Philanthropy Group to establish it and maximize its impact. “It’s really major,” says Lavigne of the undertaking. “So much goes into it, it’s insane. It’s major. You have do everything politically correct and properly. Trevor Neilson manages it and his company [GPG] does Angelina and Brad and Bono, all their charities, so I’m in with the big dogs and the major people. We have so many projects that we’re developing right now but I’m excited to get going.”

Lavigne is currently on a cross-Canada tour behind her fourth and latest album, Goodbye Lullaby, which was released in March. “When I get a break, I’ll write,” she says of new material. “I have a couple of songs in my back pocket that I’ve saved from the new record, but right now Canada is the last stop for the Black Star Tour. I’m [here] for a month and I’m really excited to just be back.”

Click here to check out a few pieces from Avril’s Abbey Dawn Spring/Summer 2012 collection!