Lady Gaga and Usher were just two of the big names at Saturday's A Decade of Difference concert, and not only did Gaga serenade the former president and drop an F bomb during the show, but Usher danced up such a storm he ripped his pants!

The concert celebrated the tenth anniversary of the William J. Clinton Foundation, and it also featured performances by Juanes, Kenny Chesney, K'naan and The Edge & Bono. Guests and speakers included Ashton Kutcher, Lindsay Lohan, Barbra Streisand, Ellen DeGeneres, Portia DiRossi and Maria Bello, and Ben Stiller, Matt Damon, Sean Penn, Jack Black and Kevin Spacey all taped bits for the show.

Click the video below to watch Gaga's set, and click after the jump to see Usher's wardrobe malfunction!

Move over Kate Middleton, your little sis Pippa is stealing the spotlight!

Music mogul/superstar Usher has just revealed he wants to feature Pippa Middleton's "perfect bum" in his upcoming lingerie line!

Usher is releasing his first line of sexy undies this summer, and he gushed to Britain's Look magazine he wants Duchess Catherine's little sister to be the face of his new line.

The OMG singer confessed:

"I don't think there's a more beautiful, more stunning, more talked-about woman in the world at the moment. I'm going to be approaching her in the next few weeks and setting up a meeting this summer."

What would the Queen say?

Usher went on to express: "The great thing about her is that she would be a global brand. Everybody knows her now, she would be perfect. I am sure everybody is trying to sign her up and she won't be cheap, but she has the looks and the popularity to really establish a new product."

Get in line, Usher. Miss Middleton doesn't have a Facebook page dedicated to her perfect booty for nothin’!

Usher is completely in love with his son Usher Raymond V ... and it shows!

After enjoying lunch at West Hollywood's Real Foods Daily restaurant, the duo hit the streets for an afternoon walk. Joining them ... Usher's godfather, Ben Vereen. Looks like the little tot has a fascination with motorcycles!

No doubt, this little boy has killer style just like his famous daddy! See a photo of Usher being the doting dad ... after the jump.

Seth Browarnik/WorldRedeye.com

A|X Armani Exchange and 944 Magazine hosted the second annual Neon Carnival in Palm Springs Saturday during the Coachella music festival.

Celebs like Paris and Nicky Hilton, Rihanna, Usher, Kellan Lutz and Kelly Osbourne enjoyed carnival games and thrill rides like bumper cars, kite runners and slides.

Coachella on a VIP pass ... must be nice!

Click through to check out pix of Kellan and Kelly ...

Beyonce, Mariah Carey, Usher and 50 Cent are facing calls from music industry insiders to return the millions they made performing for members of controversial Libyan leader Muammar Qaddafi's family members.

Mariah Carey reportedly earned $1 million in 2008 to sing only four songs for Qaddafi's son, Muatassim, during a New Year's Eve bash in St. Barts.

Beyonce and Usher also performed for an undisclosed sum for family members on the same Caribbean island just one year later. 50 Cent performed for Muatassim at a 2005 film festival in Venice.

"If it were me, it would go to charity," says Buck Williams, an agent for R.E.M. and Widespread Panic. As for what these performers, who are millionaires several times over, should do with this cash, "Hopefully donate it to a charity that somehow assists some of the people who have suffered at the hands of that regime," an agent for Arcade Fire told Rolling Stone.

Artists faced similar criticism decades ago after playing at a resort in South Africa during apartheid. Rod Stewart, Queen and the British band Status Quo donated money to charities after facing similar outcries.

But despite the current unrest going on in his country, Quaddafi didn't suddenly become a bad guy. In 1988, he ordered the bombing of a Pan Am flight over Lockerbie, Scotland, which resulted in the deaths of 270 people. So why would they perform for such a corrupt ruler in the first place?

"Ninety percent of the time the artist has no clue," says Williams. "I don’t think most artists go into [performing at a party like this] with that kind of in-depth focus, [of] how each country is governed and what goes on inside each country," an agent for Metallica, Billy Joel and Rod Stewart said. "Not every artist is a humanitarian. In more cases than not, for people, greed rules."

But for one artist, that's clearly not the case. On Friday, Nelly Furtado tweeted:

"In 2007, I received 1million$ from the Qaddafi clan to perform a 45 min. Show for guests at a hotel in Italy. I am going to donate the $"

The pre-Grammy bashes have already started, and last night partygoers at the Belvedere Red event at Avalon got more than just a performance by Usher -- they witnessed a bar brawl between Jamie Foxx and another patron!

Sources inside tell X17online that right before Usher took the stage, a man tried to hit Foxx, and the actor/singer threw back a punch to retaliate. Security guards broke up the fight, and Foxx was escorted to his car by a team of bodyguards after the show. Foxx was not hurt, and the police were not called, so it sounds like this is the last we're going to hear of this!

Click the gallery below to see who else showed up to the star-studded event!

After Usher bailed out of a rescheduled Berlin show on Wednesday evening, the R&B star has now cancelled this weekend's concerts in Holland, Germany and Belgium, due to a respiratory illness.

Usher's rep released the following statement on the matter:

"Usher is suffering from an upper respiratory illness which is currently preventing him from performing a proper show. After consultation with doctors, he has been advised to reschedule the upcoming dates in order to get the rest he needs to ensure a complete recovery."

Usher was quoted as saying, "I have been very excited about my European tour and I deeply regret having to reschedule the shows. I am truly sorry for any inconvenience I have caused my fans. My fans are the best in the world and I am looking forward to getting better so that I can give them the show they deserve."

According to his management, Usher wasn't "feeling well" on Wednesday, and after singing just five songs and getting booed by the audience, he left the stage. The singer is due to kick off the UK leg of his world tour in Manchester on January 26, so hopefully he'll be recovered by then!

While set to perform in Germany, Usher has come down with a bug ... or has he? The R&B singer canceled his Berlin show on Wednesday last minute ... after keeping the audience waiting for more than forty minutes. According to his management, he wasn't "feeling well."

The singer released the following statement:

"I am truly sorry to all my fans in Berlin who were inconvenienced by tonight's postponement of the show. I was ill and felt that I would not have been able to give them the show that they properly deserve. I am looking forward to performing tomorrow and giving Berliners a great show."

Usher was reportedly seen out at local bars after the cancellation.

During last night's show, Usher hit the stage but gave his Berlin fans a less-than-stellar performance ... only singing five songs. Audience members also say Usher's voice was "not up to par." He eventually realized this, and apologized to the crowd. As a result, the booing began.

Usher's trucks are headed for Lyon, France right now. Let's see if he's feeling well enough to hit the stage. For his fans' sake, we hope so!