"I'm more insecure than I ever let anyone know," Zeta-Jones, 37, tells InStyle in its July issue.
The actress, who won the Best Supporting Actress Oscar for Chicago in 2003, admits: "Sometimes you protect yourself with this kind of armor that people see more than they see you."
And although she and husband Michael Douglas have homes in, among other places, Bermuda and Majorca, Spain, she's determined that their kids Dylan, 6, and Carys, 4, are modest and well-behaved.
"We believe in good manners," she says. "There's nothing worse than spoiled rich kids."
Though Dylan and Carys attend school in Bermuda, they wear traditional British uniforms and make yearly visits to Zeta-Jones's native Wales, which she wants her children to be proud of. "They can sing 'Jingle Bells' in Welsh!" she tells InStyle.
"Years ago if someone said they were doing a movie in Romania, I was, like, 'What time is my flight?' " she says. "I couldn't see beyond the script. Now, I'm like, 'Script? I'll figure that out after dealing with the people I love more than anything in the world.' "