"Oprah called me and was like, 'Hey girl, do you want to ride together?' " the 26-year-old Oscar contender told PEOPLE at Thursday's third annual Essence Black Women in Hollywood luncheon.
"I was like, 'I got it Oprah, calm down. I don't want to show up with you. People will think we're too cool."
Despite refusing Oprah's offer, the young actress's love for the mogul definitely runs deep.
"She's the only person that I'm continually star-struck by," admits Sidibe. "When I meet people I get used to them very quickly because everyone seems like a friend because I watch them on TV. But Oprah is the only one I can't get used to."