Winfrey spoke with ET's Nancy O'Dell at the premiere of her new OWN drama, Greenleaf, and the media mogul opened up about the possibility of America electing its first female president.
"I really believe that is going to happen," said Winfrey, 62. "It's about time that we make that decision."
"Regardless of your politics, it’s a seminal moment for women," she continued. "What this says is, there is no ceiling, that ceiling just went boom! It says anything is possible when you can be leader of the free world."
"I'm with her," Oprah added, touting Clinton's campaign slogan and effectively endorsing the former Secretary of State. Clinton, the presumptive Democratic Party nominee for president, was also recently endorsed by President Barack Obama, who declined to back any candidate until the primaries had ended.
"This is the reason James Corden is so great: He is completely 100% himself and his enthusiasm makes you want to be enthusiastic," Winfrey explained. "You think, if anyone is that excited, I want to know what all the excitement is about. His enthusiasm is so pure and so real."
"I thought the 'Carpool Karaoke' with all the Broadway stars was one of the best ever," Winfrey shared. "I mean we thought Adele was great, we thought Stevie Wonder was great, we thought George Clooney and Julia Roberts was great. But when all of those Broadway stars [got] in that car, and you love Broadway, you're just like, 'Ahhhh! That was good!'"
However, despite her love of the hilarious segment, Winfrey swears fans won't ever see her getting in the passenger seat with Corden.
"Listen I think the point of Carpool Karaoke is that you can sing," she explained.
"George Clooney and Julia Roberts can't sing, they proved that," O'Dell pointed out.
"Yeah but they're George Clooney and Julia Roberts," Winfrey replied. "You will not see me do it."
Fans will, however, get to see the beloved entertainment icon's very own cookbook.
Winfrey recently revealed she's releasing Food, Health and Happiness: 'On Point' Recipes for Great Meals and a Better Life
, and she couldn't be more excited.
"It's really my food story because I have had a long journey with food that I think I finally resolved," she shared, adding, "I'm not saying I'm cooking everyday but I do cook and I have chefs who cook, so it's all of those chefs' ideas and my ideas."