In the 26 years since Paul Simon released "Graceland," his album has secured its place in music history. It's considered by many to be one of the greatest records of all time.

Oprah Winfrey would not disagree.

In the new documentary "Under African Skies," which is premiering at Sundance, Oprah reveals "Graceland" is her favorite album ever (Stevie Wonder's "Songs in the Key of Life" ranks second in her book).

When "Graceland" came out in 1986, it was an instant sensation, dazzling audiences with its mixture of Simon's lyrical prowess and the musical rhythms of South African musicians, including Ladysmith Black Mambazo.

But Simon quickly came under attack by some critics who said his collaboration with those musicians violated the United Nations' cultural boycott of the apartheid regime in South Africa.

The documentary "Under the African Skies" retraces the controversy, and Simon's return trip to South Africa last year to mark the 25th anniversary of "Graceland." In the film, Oprah admits that the controversy surrounding the record almost persuaded her to never give it a try.

In an interview with CNN at Sundance, Simon said the intervening years had demonstrated to him that cultural boycotts of the sort imposed on South Africa were counterproductive. Rather, he suggests, the success of "Graceland" exposed many people to what was going on in that country under apartheid.

We asked Simon how he felt that no less a figure than Oprah loves "Graceland," and he revealed he's known for a while of Oprah's high opinion. Trying to suppress a smile, he admitted it was pretty cool.