Oprah Winfrey is giving $12 million to a museum being built on Washington’s National Mall that will document African-American history, officials said Tuesday.The media mogul and former talk-show host previously gave $1 million to the National Museum of African American History and Culture, and the museum says her $13 million total contribution is its largest to date. As a result, the museum’s 350-seat theater will be named after Winfrey, who is also a member of its advisory council.Construction on the $500 million museum began in early 2012. When it’s finished in 2015, the museum will be the 19th Smithsonian museum. The U.S. government is providing half of the funding. To date, about $140 million has been raised in private funds."I am deeply appreciative of those who paved the path for me and all who follow in their footsteps. By investing in this museum, I want to help ensure that we both honor and preserve our culture and history, so that the stories of who we are will live on for generations to come,” Winfrey said in a statement released by the museum.Lonnie Bunch, the museum’s director, said that Winfrey has been very involved in the museum’s creation and that he wouldn’t be surprised if she was one day on the stage of the theater that will bear her name.The museum is also in talks with Winfrey to acquire memorabilia from her career, Bunch said. He said he’d love to have a microphone used on her television show to add to the museum’s collection of over 22,000 objects.Those objects help tell the story of African-American history from slavery to the post-Civil War period, the civil rights era, the Harlem Renaissance and the 21st century.