Oprah Winfrey says Kim Kardashian's explanation for her short-lived marriage to Kris Humphries "leveled" her.

An interview by the media mogul with the entire Kardashian clan television stars is due to air on Sunday on her network OWN.

Oprah has revealed that the 31-year-old's split from the basketball player in October will be addressed in the program, Oprah's Next Chapter. "Everyone who's asked was the marriage a publicity stunt? Why did she leave after 72 days? Her answer leveled me," she wrote on her Facebook page.

Oprah hinted more about what will feature in the one-hour chat: "I genuinely wanted to know why they have become a cultural phenomenon, why so many people love to watch their every move and why so many others love to hate them. Are they completely ego centered? Are they really 'famous for being famous' or is there something more?"

"Those of you who watch [Keeping Up With the Kardashians] know they hold nothing back. This interview I'd say was another level of forthrightness and honesty," the 58-year-old added.

Oprah clarified that she had to do plenty of research before the enlightening chat: "I had never met them, nor seen the show. I did a full on Kardashian Kram in preparation, watching major shows from every season."