The performance was part of the annual Power of Love Gala at the Bellagio Resort, which raised money and awareness for the Lou Ruvo Brain Institute.

ABC News reports that Siegfried Fischbacher & Roy Horn’s manager Bernie Yuman announced the comeback performance at last year’s event and said it was the duo’s way of proving that brain injuries and illnesses can be overcome. Fischbacher told ABC the duo felt it was an important thing to do.

Having lived through Roy’s recovery, watching how amazing the human spirit can be, we just want to pass along the kind of help we’ve received. We’ll know we’re not onstage just for ‘Siegfried & Roy,’ but for every patient who the Ruvo Institute can help.

Horn was attacked onstage by one of his tigers in October 2003 and, despite the great possibility he’d never speak or walk again, battled his way back from his injuries.

The tension of the already emotionally-charged performance was further amplified when Yuman announced shortly before the show that the white tiger onstage with Siegfried & Roy was none other than Montecore, the animal who attacked Horn more than five years ago.

Yuman also dismissed reports that Horn is battling a condition that causes bleeding in his lungs and was putting his health at risk by performing, telling the Las Vegas Review-Journal, “That’s crazy crap. Roy has nothing wrong with him. He is in perfect health considering he’s gone through this very debilitating experience.”

The Las Vegas Sun’s John Katsilometes blogged live from the gala and did his best to capture the excitement and spectacle of the evening, including a blow-by-blow of the duo’s farewell performance.

Danny DeVito and wife Rhea Perlman are in the room. So are Steve Schirippa and Hilary Duff. Larry Ruvo is reading off the list from the podium. Teri Hatcher, in here somewhere. Muhammad Ali is expected, too. The show was opened by comic John Pinette. John Paul Dejoria, who made the first-ever donation to Keep Memory Alive, was just introduced.

Very odd sighting (and an assist to Kate Bennett for spotting him): Perry Farrell of Jane’s Addiction. He’s a longtime fan of S&R, for their “style onstage,” and was asked by event organizers to take part. He performed at LAX last night and said this event is “very, very Vegas…”

Women painted as white tigers were crawling all over the silent auction. They were quite lifelike but refused to growl.

10:25 p.m.
“Ladies and gentleman, the spirit of Siegfried & Roy has arrived,” a voice intones, followed by a piano and orchestra arrangement. Horn is onstage, caped in black hood, white shirt and mask. He opens a silver lid atop a box, and flames pour out. He closes it, reopens, and Siegfried emerges, to applause.

A stage platform is rolled out, and at the left is a caged white tiger. Siegfried drapes the cage with a white cloth, then moves to the middle of the set and is also concealed in white. Roy pulls a rope to display a tiger in his place and Siegfried inhabiting the first cage. Roy’s voice is heard over the speakers, he is talking of dreams. The tiger is led from the cage by Siegfried and lays near both performers, who pull off their masks.

The tiger is uncaged and off the leash. The crowd stands and cheers. Roy is still moving unaided. Siegfried waves, and the curtain closes.

About eight minutes in length, more than a year in the making, more than five years since Roy’s life-threatening injuries. “The spirit of Siegfried & Roy has left the building,” the voice says. And there is your moment in Vegas history.

Yeah, it’s cheesy as heck, but in a good way. Siegfried & Roy’s farewell is the end of an era for Las Vegas. The duo’s impact – financial and otherwise – on the city and their contributions to the development of the Strip’s modern big budget entertainment spectacles can’t be dismissed.

Siegfried & Roy will be the subject of a special edition of “20/20” that will cover “the story of their rise to fame in Las Vegas, the tragic events onstage that nearly cost Horn his life, and the dramatic rehab that made the performance Saturday night possible.”

The show airs March 6 at 9 p.m. ET on ABC.

Read ABC’s coverage of Siegfried & Roy’s farwell and watch an exclusive clip from the performance here.

Read John Katsilometes’ blog in the Las Vegas Sun here.

Read the Las Vegas Review-Journal coverage here.