Jessica Biel understands that sex-ed isn't just for awkward middle schoolers.
That's why the 33-year-old actress is teaming up with Saundra Pelletier -- founder of the nonprofit health care organization WomanCare Global -- to launch a series of online videos on womancareglobal.org that will cover everything from puberty to contraception.
"We share girl stories, fears, and insecurities," Biel tells Glamour about her new project. "The tone is informative but also goofy, smart, witty."
WATCH: Jessica Biel and Justin Timberlake Happily Step Out Together for the First Time Since Birth of Baby Silas
The usually private former 7th Heaven star says she was "shocked" when she herself didn't understand what was going on with her own body after she decided to go off birth control two years ago.
"I've been on the Pill for so long; how hard will it be to get pregnant?'" she recalls she found herself wondering after making the big decision. "Suddenly I realized I really didn't know what's going on inside my own body. It was shocking."
The actress says she's also taking part in the project so that other women won't feel "ashamed" or "gross" about their body issues -- she had that particular experience firsthand when she got her period in the fifth grade.
"I was in a school play, wearing a gray beard and this pad the size of a skateboard and thinking, What is happening to me?" she shares. "We want girls to know what their [body is going through] so they don't feel scared or ashamed or gross."
"Sometimes you have to have the courage to stand up for what you believe in," she adds about her surprising new venture.
Biel and her husband, Justin Timberlake, welcomed their first child, Silas Randall, in April and the new mom couldn't help but gush about her baby boy at a recent event. "She said she loves being a mom and that Silas is a really easy baby," a source tells ET. "He's smart and engages with people, very curious."
WATCH: Jessica Biel Looks Amazing in Rare Public Appearance Post-Baby
Timberlake also couldn't help but brag about his son on The Tonight Show, showing off pics of his five-month-old to Jimmy Fallon. Watch below!