Botching anthem, Jamie Foxx is one celeb too many at Mayweather-Pacquiao

Tons of celebrities made it to the so-called Fight of the Century on Saturday night in Las Vegas, and Floyd Mayweather won, but it looks as if Jamie Foxx and not Manny Pacquiao was the night's biggest loser.

Tapped to sing "The Star-Spangled Banner" before the battle, Foxx went freestyle with the melody, adding enough to the national anthem to satisfy an entire season of "American Idol."

Hey, at least he remembered all the words. We're looking at you, Christina Aguilera, and you, Cyndi Lauper, and you, James Taylor. (Miley Cyrus, you and national symbols are a whole 'nother story -- one that we'll leave alone.)

Photos | 10 questionable national anthem performances

And then, well -- then Foxx added insult to injury and posed for a picture with Justin Bieber.

Biebs in tha building! @justinbieber #MayPac

A photo posted by Jamie Foxx (@iamjamiefoxx) on May 3, 2015 at 12:37am PDT

Which of those moves was the less wise is anyone's guess.

"It's about to go down!!! #MayPac #NationalAnthem," the "Ray" Oscar winner (Yup, dude can sing) had tweeted enthusiastically ahead of the event. "Getting ready to get my sang on at #MayPac then sitting ringside with @SamsungMobileUS. Living that #GalaxyLife."

Twitter didn't react as enthusiastically after the deed was done -- much like the reaction Foxx got when he joked about Bruce Jenner's gender transition at the iHeart Radio Music Awards in March.

Photos | Mayweather vs. Pacquiao: Celebrities gather for fight night

There was a bright spot, however. No matter what it looked like on camera, Foxx's "Jarhead" costar Jake Gyllenhaal was not laughing hysterically at the performance, just laughing hysterically during the performance, according to TMZ Sports. Gyllenhaal's rep told the website that the actor and his director buddy Antoine Fuqua "were laughing at something completely unrelated to Jamie's performance."

Still, guys -- it might not have sounded exactly like the national anthem, but it was the national anthem. A little respect, please?

See more of the many stars who made the scene by clicking on the photo gallery link above -- it seems there were so many A-listers in town, McCarran International Airport had to pack in the private jets wing-to-wing on the tarmac and eventually started sending smaller planes to two other area airports.

Follow Christie D'Zurilla on Twitter @theCDZ and Google+. Follow the Ministry of Gossip on Twitter @LATcelebs.