1. Princess Diana and Prince Charles: When ET premiered in 1981, everyone was obsessed with Princess Diana's wedding. Over 750 million people watched her say "I do" to Prince Charles during the two-hour ceremony at St. Paul's Cathedral in London, England.
2. Prince William and Kate Middleton: In 2011, 30 years after his mother's nuptials, Prince William's wedding became the most-watched of all time, as 2 billion viewers tuned in on TV and the Internet when the royal couple exchanged vows at Westminster Abbey in London, England.
3. Arnold Schwarzenegger and Maria Shriver: The 1986 ceremony boasted an incredible guest list that featured John F. Kennedy Jr., his mom Jackie O. and even Oprah Winfrey. Maria filed for divorce from Arnold in July 2011, though their divorce has never been finalized. The two split after it was revealed he fathered a son more than 14 years earlier with an employee, Mildred Baena.
4. Donald Trump and Marla Maples: The Donald's second time at the altar rivaled Schwarzenegger's nuptials in terms of famous guests. O.J. Simpson, Howard Stern and Rosie O'Donnell were among the famous guests who witnessed the business mogul enter into holy matrimony with his bride in 1993. The couple have a 22-year-old daughter, Tiffany, but split in 1999. Donald married again in 2005 to model Melania.
5. Marie Osmond and Steve Craig: The couple first wed in 1982, during a lavish ceremony that included roughly 7,000 guests. Marie and Steve re-married in 2011 after divorcing in 1985. For their second wedding, Marie wore the same gown from the 1982 ceremony.
6. Liza Minelli and David Gest: When this power couple wed in 2002, Michael Jackson was best man and Elizabeth Taylor was matron of honor. They called it quits in 2007.
7. Kevin Costner and Christine Baumgartner: Kevin swept his bride right off her feet in 2004, when they said "I do" on his Aspen ranch. After the ceremony, the couple rode up to our cameras on their ATV to show off Christine's blinding ring. They have three children together: Cayden, 8, Hayes, 6, and Grace, 5.
8. Celine Dion and Rene Angelil: Despite their age difference -- Rene is 26 years Celine's senior -- the two fell in love and wed in December 1994. The singer made headlines with her heavy headdress made of Swarovski crystals.
9. Tom Cruise and Katie Holmes: The movie stars had the most adorable flower girl, their daughter Suri, for their 2006 wedding inside a converted 15th-century armory in Italy's Odescalchi Castle.