Zaire's President Mobutu Sese Seko, center, as he raises the arms of heavyweight champ George Foreman, left, and Muhammad Ali, right, in Kinshasa, Zaire, which is now known as the Republic of Congo, Sept. 22, 1974.

Muhammad Ali as he chants to fans during a sightseeing tour downtown Kinshasa, Zaire, which is now known as the Republic of Congo, Sept. 17, 1974.

Perspiration flies from the head of George Foreman as he takes a right from challenger Muhammad Ali in the seventh round in the match dubbed Rumble in the Jungle in Kinshasa, Zaire, which is now known as the Republic of Congo, Oct. 30, 1974.

Muhammad Ali, right, as he stands back as referee Zack Clayton calls the count over opponent George Foreman, red shorts, in Kinshasa, Zaire, which is now known as the Republic of Congo, Oct. 30, 1974.

Challenger Muhammad Ali watches as defending world champion George Foreman goes down to the canvas in the eighth round of their WBA/WBC championship match in Kinshasa, Zaire, which is now known as the Republic of Congo, Oct. 30, 1974.

George Foreman and Muhammad Ali in action at the Heavyweight Championship fight, Oct. 30, 1974, in Kinshasa, Zaire, which is now known as the Republic of Congo.

George Foreman and Muhammad Ali compete in the Rumble in the Jungle heavyweight fight in Kinshasa, Zaire, which is now known as the Republic of Congo, Oct. 30, 1974.

Muhammad Ali holds the torch before lighting the Olympic Flame during the Opening Ceremony of the 1996 Centennial Olympic Games in Atlanta, July 19, 1996.

American Former World Heavyweight boxing champion George Foreman holds his week-old son, George Foreman III, Houston, Jan. 29, 1983.

Lonnie Ali, Muhammad Ali, then President Bill Clinton, and Jim Carrey onstage during the Grand Opening Gala for the Muhammad Ali Center at the Kentucky Center in Louisville, Ky., Nov. 19, 2005.

George Foreman poses while launching his "Lean, Mean Fat Reducing Grilling Machine, " Nov. 22, 2001, during a press conference in London.

Muhammad Ali, Lonnie Ali, and Jennifer Lopez attend Muhammad Ali's Celebrity Fight Night XIX at JW Marriott Desert Ridge Resort & Spa, March 23, 2013, in Phoenix.

U.S. Rep. Al Green (D-TX) presents a Phoenix award to former boxer George Foreman at the Congressional Black Caucus Foundation Annual Phoenix Awards dinner, Sept. 24, 2011, in Washington.

PHOTO: Robin Williams and Muhammad Ali during Muhammad Ali's Celebrity Fight Night XII - Inside at JW Marriott Ridge Desert Resort in Phoenix, March 18, 2006.

George Forman throws out the ceremonial first pitch before the game between the Baltimore Orioles and Houston Astros at Minute Maid Park, May 30, 2014, in Houston.