Boxing legend Muhammad Ali sits with his wife, Yolanda, as they await the inauguration ceremony of Barack Obama as the 44th President of the United States. REUTERS/Jim Young

Muhammad Ali accepts the President's Award accompanied by his wife Yolanda Williams at the 40th Annual NAACP Image Awards. REUTERS/Mario Anzuoni

Muhammad Ali poses with an enlarged copy of a new Wheaties cereal box adorned with his photo at a press conference in New York. REUTERS/File

Muhammad Ali, along with his wife Lonnie, react to a story told by actor Kevin Costner at the Muhammad Ali Celebrity Fight Night awards banquet in Phoenix. The event raised money for the Muhammad Ali Parkinson Center and other charities. REUTERS/Jeff Topping

Laila Ali hugs her father after winning her super-middleweight fight against Asa Sandell of Sweden in Berlin. REUTERS/Arnd Wiegmann

Former world heavyweight boxing champion Muhammad Ali watches his 21-year-old daughter Laila Ali in her debut as a professional boxer. Laila beat middleweight opponent April Fowler in a first round knockout. REUTERS/File

Muhammad Ali jabs at photographers while arriving at the Orpheum Theatre for the premiere of the film "Collateral" in Los Angeles.

President George W. Bush awards Muhammad Ali with the Presidential Medal of Freedom, as Ali's wife Lonnie watches. REUTERS/Kevin Lamarque

Former President Bill Clinton hugs Muhammad Ali as his wife Lonnie Ali looks on during the grand opening gala celebration of the Muhammad Ali Center at the Kentucky Center for the Arts in Louisville, November 2005. REUTERS/John Sommers II

Muhammad Ali poses during the World Economic Forum in Davos, Switzerland. REUTERS/Andreas Meier

Muhammad Ali is assisted as he enters the funeral for boxer Joe Frazier at the Enon Tabernacle Baptist church in Philadelphia, November 2011. REUTERS/Tim Shaffer

Muhammad Ali poses with a copy of his book, The Greatest Of All Time, at the Frankfurt book fair. REUTERS/Kai Pfaffenbach

Muhammad Ali watches during the first quarter of the 2009 NBA All-Star basketball game in Phoenix. REUTERS/Rick Scuteri

Muhammad Ali and his wife Lonnie follow the super-middleweight fight of his daughter boxer Laila Ali against Asa Sandell of Sweden in Berlin. REUTERS/Pawel Kopczynski

Muhammad Ali eats a piece of his birthday cake as boxer Mike Tyson looks at the MGM Grand hotel in Las Vegas. Ali was celebrating his 57th birthday. REUTERS/File

Muhammad Ali is given the Courage Award by singer Whitney Houston at the GQ Men of the Year awards show in New York. REUTERS/Jeff Christensen

Muhammad Ali and actor Denzel Washington pose for photographers at the 'Boys & Girls Clubs of America' annual President's dinner, in New York. REUTERS/Dave Allocca