Troops were so excited they gang-tackled Williams into autographing dozens of photos of himself, posing for pictures and displaying his rapid-fire humor.
The three stars landed in Baghdad along with Gen. Richard Myers, chairman of the U.S. Joint Chiefs of Staff, in military helicopters for a visit to boost troop morale during the holiday season.
The VIPs were greeted with deafening cheers from soldiers representing units including the 1st Cavalry Division based in Fort Hood, Texas; the 256th Brigade of the Louisiana National Guard, and the 2nd Bridged of the 10th Mountain Division out of Fort Drum, New York.
"I know we in America wouldn't have the life we have if it wasn't for people like you," said Tweeden, who visited Baghdad last year with Williams for a pre-Christmas event organized by the United Service Organizations.
Former Denver Broncos great Elway said he thought twice about making the Baghdad trip, considering the worsening security situation.
"But once my kids told me that it'd be a great idea, I knew it was the right thing," he said before showing off his trademark quarterback skills by tossing several balls into a crowd of clambering soldiers.
"I'm not funny, I'm not pretty, but I can sure throw a ball," he said.
The USO is a nonprofit charity organization established before World War II to boost morale, provide welfare and deliver recreational services for American troops.