updated 03/14/2011 AT 01:00 AM EDT
•originally published 03/14/2011 AT 01:00 AM EDT
Reese Witherspoon (flashing plenty of emeralds in her platinum-and-diamond ring and earrings by Neil Lane) gabbed with Elizabeth Banks (in vintage Versace) at the Vanity Fair Oscar Party at the Sunset Tower Hotel. "I feel really lucky to be a part of it!" said Witherspoon of the hoopla.
THE VANITY FAIR OSCAR PARTY
THE SUNSET TOWER HOTEL
The Social Network's Justin Timberlake cozied up to girlfriend Jessica Biel, then mingled with pals Jamie Foxx and Andrew Garfield.
LADY IN RED
Sandra Bullock "was in a great mood," says an onlooker of the actress, who chatted with Mick Jagger.
THE SINGLE GUY
Though he stopped to talk to ex Taylor Swift, Jake Gyllenhaal went stag for the night.
Justin Bieber and Selena Gomez took their romance public at the Vanity Fair party, holding hands and kissing. "They were so sweet," says a guest.
Gomez and Bieber put on a show inside the party's photo booth.
GIRLS' NIGHT OUT
Cameron Diaz (in Carolina Herrera) met up with pal Gwyneth Paltrow (in Michael Kors).
Madonna (in Francesco Scognamiglio) and daughter Lourdes, 14 (in AllSaints), at the Vanity Fair party before heading to Mom's bash at manager Guy Oseary's house in L.A.
THE GOVERNORS BALL
GRAND BALLROOM, HOLLYWOOD & HIGHLAND CENTER
The Fighter family (from left: Christian Bale and wife Sibi Blazic; Mark Wahlberg and wife Rhea Durham; Amy Adams) toasted their knockout night with Moet & Chandon.
"My favorite part of the night was seeing the Social Network guys!" said Hailee Steinfeld (getting a squeeze from True Grit costar Jeff Bridges).
"When Natalie won, I breathed a sigh of relief!" said Black Swan director Darren Aronofsky (with Mila Kunis).
THE ELTON JOHN
AIDS FOUNDATION ACADEMY AWARDS VIEWING PARTY, PACIFIC DESIGN CENTER
"Everyone was obsessed with him," says a guest of Steven Tyler (with John, whose bash was sponsored by Chopard, Jo & Raffy Manoukian and Godiva).
Joel Madden surrounded himself with former and current reality TV stars, including (from left) his wife, Nicole Richie, Kim Kardashian and Kelly Osbourne.
Though he didn't perform, Prince (with guest) held court with John, who duetted on "Tiny Dancer" with Florence + the Machine.
The Kids Are All Right's Josh Hutcherson hit the floor with Vanessa Hudgens (left) and Ashley Tisdale (in a Jenny Packham gown).
Cee-Lo Green (left) got cozy with fellow music stars Seal, Chaka Khan and REM's Michael Stipe (right).