Since they've been friends for years, Oprah knows the topic that's closest to Maria Shriver's heart—motherhood.
Along with her husband, Arnold Schwarzenegger, the first lady of California is the proud parent of four kids—Katherine, Christina, Patrick and Christopher.
She is also the daughter of Eunice Kennedy Shriver. Maria says her feelings about motherhood are inherited from Eunice. "She was raised by a very strong mother," Maria says. "So she really raised me to think of that as a really important part of my life, a role in my life, and the most important thing I would ever do."
Maria likes talking about motherhood so much that she'll talk to anybody about it. "It's the one thing I do constantly," she says. "When I see kids get along well, I go, 'Let me talk to your mother. How did she do that?'"