Avril Lavigne Sings on 'GMA'

In just three years, Avril Lavigne has sold more than 21 million records. Her first album, "Let Go," put her on the map and turned wearing a tie into a girl thing.

Lavigne appeared in New York City's Bryant Park to sing hits "He Wasn't" and "My Happy Ending" from her latest album "Under My Skin" for "Good Morning America's" Summer Concert Series. Her performance concluded with "Sk8er Boi" from "Let Go."

She is currently on a worldwide tour called "Bonez" for her latest album, "Under My Skin."

"I've been touring for a year straight and I feel great," Lavigne said.

Her second album, "Under My Skin," truly showcases Lavigne's talents. In addition to the guitar, she plays drums and the piano. She co-wrote all the songs with singer-songwriter Chantal Kreviazuk. Released in May, the album has already sold more than 7 million copies.

There's big news in Lavigne's personal life, too. The 20-year-old rocker recently got engaged to fellow Ontario native Deryck Whibley, Sum 41's lead singer. And, she's sporting quite a ring!

Lavigne arrived on the music scene in the summer of 2002 with the single "Complicated." Her hard-core sound immediately differentiated her from other teen pop stars, and won her a loyal group of devoted fans.

The rocker, who grew up in a devout Christian household in a small town, said her family is happy about her musical career.

"They're super proud and they're all cool with it," she said.