Miranda Kerr says it was her decision to leave Victoria's Secret. Credit: Gregg DeGuire/WireImage.com

Last week, Us Weekly revealed that model Miranda Kerr's three-year contract with Victoria's Secret wasn't being renewed. One industry insider said that Kerr was "not a big seller for VS" while another source noted her "difficult reputation."

Now, the Australian stunner and wife of Orlando Bloom confirms she's no longer committed to the lingerie company and  shares her side of the story. "This is a natural evolution," she tells The Sydney Morning Herald of her departure from Victoria's Secret. "The thing is, I've been modeling since I was 13. I'm now entering a new phase in my life. I have felt this coming since my son was born and, after I became a mother, I realized I needed to prioritize my time," Kerr explains.

The 29-year-old model, who's mom to Flynn, 2, says she simply has too many projects on her plate and continuing her role as a Victoria's Secret Angel would be too time-consuming. "'I'm just not in a position to commit to a full contract at this time," she said. "It's three months at a bare minimum."

Among the projects the burgeoning entrepreneur is working on: the release of her second book, Empower Yourself; her skin care line, Kora Organics; and campaigns for Quantas, Mango, and other other companies.

Kerr, who turns 30 on Saturday, April 20, also shared her birthday plans with the newspaper. Bloom is throwing a private party at their home. "He knows I like to dance and he knows I like to sing and I have the most fun when I'm singing and dancing -- so I think there might be a little karaoke going on," she revealed.