The 59-year-old TV queen, who is known for her philanthropic initiatives, is set to pool in thousands of dollars for the charity, reported Contactmusic.
The highest bidder will get to meet Winfrey either at the film's New York premiere dated August 5 or in Los Angeles on August 12.
Winfrey, who has been cast opposite Forest Whitaker in the movie, will be seen playing Gloria Gaines, the wife of presidential butler.
The film is based on real-life account of Eugene Allen, a White House butler and also stars Robin Williams as Dwight Eisenhower, Alan Rickman and Jane Fonda as President Ronald Reagan and First Lady Nancy.