President Barack Obama, Oprah Winfrey, Barbara Streisand and Steven Spielberg are among the guests invited to Chelsea Clinton’s wedding, according to The Hudson Valley News.Among the other celebrities who could be among the 500 people expected at the July 31 event are Ted Turner, former British Prime Minister John Major, and historian Doris Kearns Goodwin, reports the paper, which serves the upstate New York area.The Associated Press has reported that Clinton's wedding to Marc Mezvinsky will take place July 31 in Rhinebeck, N.Y., about two hours north of New York City.Meanwhile, Hillary Rodham Clinton says she's not letting the demands of global diplomacy stop her from planning daughter's wedding.A Polish TV interviewer asked how she manages juggling being secretary of state and mother of the bride.Clinton agreed that both are "serious, important and stressful.""Luckily we have email now. I can communicate and people can send me pictures of flower arrangements or other kinds of decisions," she told the Polish current affairs program Tomasz Lis Live."It's a very happy time for my family. . . . It truly is the most important thing in my life right now," Clinton said about her daughter's upcoming wedding.Chelsea Clinton is a graduate student at Columbia University's School of Public Health. Mezvinsky is an investment banker.