Nicole Richie 'wants to be billionaire'

Nicole Richie is reportedly aiming to be a billionaire by 40.

The 31-year-old star has apparently been thinking seriously about her life over the last few months. She has enjoyed a career in reality television and also has a successful fashion business, which she hopes to grow over the coming months.

"She wants to be a billionaire by the time she turns 40," an insider explained to National Enquirer.

Nicole and her Good Charlotte rocker husband Joel Madden have children Harlow, five, and Sparrow, three, together. Providing the best for the little ones is apparently what drives Nicole.

She wants to take her children all around the world and thinks making money now will be of a huge benefit to the family in the long term.

"The kids won't even be in high school. They can travel and put their money to good use around the world," the source explained.

The star plans to retire from the limelight as soon as she reaches her goal as she wants to be a full-time mom.

While Joel has enjoyed success with his band and as a judge on the Australian version of reality TV show The Voice, Nicole apparently views bringing home the money as her role.

"Joel isn't nearly as ambitious," the insider said.