Celebrating with Oscar's Biggest Stars: Inside the After Parties

When the curtains closed on the Academy Awards, there is only one thing to do: party!

Beyoncé, TomKat, Marc and Jennifer and Madonna and Guy got down in pure celebrity style Sunday night.

When we caught up with the Material Girl, she told us her favorite part of Oscar night: "Al Gore."

The first party of the night was the star-studded Vanity Fair bash... or the only stop of the night if your name is Oprah Winfrey!

"I have a show to do tomorrow, and I have a cold," Oprah dished. "So this is my only party."

But while Lady O was there, she made it worth her while, chatting up Oscar winner Jennifer Hudson.

Leo DiCaprio and Kate Winslet had a "Titanic" reunion, while Oprah, Meryl Streep and Mary J. Blige hung out with Nicole Kidman while she cozied up to her hubby Keith Urban.

"Extra" also witnessed a moment between Madge and Guy, as he planted one on Madonna's cheek and then shared a moment with Gwyneth and Gwen.

Speaking of special moments, Will Smith's son Jaden wanted one: "He's coming to meet 'Buffy,'" Will said of Jaden meeting Sarah Michelle Gellar.

So what will he say to the beautiful "Buffy?"

"I don't know!" the adorable Jaden admitted.

Next, we were off to Sir Elton John's soiree, where our Terri Seymour was on hand as Elton's AIDS Foundation Oscar bash raked in more than $4 million.

"We try to raise as much money at these kinds of events as we possibly can," Sir Elton admitted.

Here, Victoria Beckham flew solo, Sharon Stone played auctioneer and "24's" Kiefer Sutherland joked with his Ironworks Record partner Jude Cole.

"We've been secretly dating for 20 years," Kiefer kidded.

Our candid cameras also caught Elton surprising Simon Cowell with a kiss, before, only on "Extra, Judge Dread revealed his true feelings about Jennifer Hudson's Best Supporting Actress win.

"It's incredible," Simon admitted. "Not teary, but I'm happy for her."

Over at the Giorgio Armani party, Adrien Brody, Leo and George Clooney partied.

"I'm wearing a suit, which I thought was important," the Sexiest Man Alive admitted. "And some very special underwear."

Proud mother Katie Holmes was also on hand, and broke news about little Suri: "She's doing really, really well... she's walking!"

But do she and Tom see more kids in their future?

"Of course, always. A couple more," Holmes said

Click on an image to view the Oscar after party photo gallery!