As if on cue, the red-carpet swarm began right at 3 p.m.

By 3:15, publicists were pulling their clients to and fro between the phalanx of media outlets along either side of the walkway — sometimes yanking them in mid-sentence if a better outlet suddenly had an opening.

Photogs yelled (“Natalie! Natalie” over the shoulder!”), starlets preened and the roar of the bleacher seats offered a moment-by-moment buzzmeter as celebs paraded by. (Gauging by the crowd vibe, Emma Stone’s red hot, Justin Bieber perhaps not as much.)

By 3:30 p.m. it was wall to wall tuxes and dress trains and all decorum was out the window. “Can you take him for five minutes,” a publicist pleaded with a TV Guide Network producer. “No! I’m backed up with ‘Glee.’?”

And on went the human horse trading, right on up through 4:59 p.m. when the last of the stragglers were shooed into the BevHilton’s International Ballroom.

“It’s like going to a bar mitzvah with a bunch of people you don’t know,” observed “Nurse Jackie” exec producer Richie Jackson, who escorted Edie Falco, in va-va-voom red, down the carpet.

But of course part of the fun of red-carpet gazing is watching the chance encounters…

Big kisses were exchanged as Ian McShane came across Scarlett Johansson (“How you doing?” McShane said, arms outstretched with his trademark smoldering stare). Natalie Portman and Lea Michele traded glances as they realize they wore the same shade of red. Eric Stonestreet had some fun with Ed O’Neill while the latter was trying to get through an “Entertainment Tonight” interview, yelling “Ed! Ed!” as he walked down the carpet.

More than one interviewer noted to Jennifer Lawrence that she “cleaned up nicely” compared to the grim wardrobe she had to work with in “Winter’s Bone.”

Laura Linney couldn’t make it because of a death in the family, but “The Big C” exec producers Darlene Hunt and Jenny Bicks brought her in spirit — a paper doll with a pic of Linney for a head.

“She’s wearing Crayola,” Bicks quipped.

Sony Corp. boss Howard Stringer was in a generous mood, citing “The Fighter,” “The King’s Speech” and “True Grit” as pics he enjoyed this year, though of course he was rooting for “The Social Network.” Most of all, Stringer said, he was happy to see a higher caliber of competitors this year, “not just a lot of late-entry indie films.”

Moments later, “Social Network’s” Armie Hammer stopped to share his Stringer story — noting that he’s spent enough time with Stringer lately to actually get to know him. “He has a great sense of humor,” Hammer said, “But it’s always a little bit funny because you feel like you’re joking around with a knight.”

AMC prexy Charlie Collier wins the prize for having it all on both coasts. He was watching the New York Jets game on WCBS-TV New York on his Slingbox device as he strolled the carpet. It wasn’t much of a nailbiter, with the Jets leading 21-11 at the time Collier made his way into the Hilton. But you know those Jets fans (“How about those Jets?” “Boardwalk Empire’s” Terence Winter asked as he walked into the backstage room after winning best drama).

But as much as industry insiders may take the glitz and glam of awards season for granted, it really is an honor, career-wise, to be in the game. So said Celine Rattray, producer of “The Kids Are All Right,” who noted that she’s poured herself into 24 previous indie pics but “Kids” was the one that got her to the dance.

“I’m so happy that we were able to speak to such a broad audience,” she said, a little wide-eyed as she took it all in.

Hands down, the most passionate group of winners to float backstage was “The Kids Are All Right” clan, and for good reason. The pic has all the hallmarks of a passion project: It was years in the making, hard to get financed, a socially conscious subject matter with an underlying message of tolerance and love conquering all.

Producer Jeffrey Hinte-Levy raised the temperature in the room by decrying “politicians who use (same-sex families) as an issue to get attention and win votes is absolutely disgusting. It’s inhumane,” he said, compared it to the same kind of “scapegoating” that has driven prejudice against African Americans and Jews. “Intolerance cannot be tolerated.”

Annette Bening said she hoped the pic would help people understand the issue of same-sex marriage.

“Maybe that’s the way our country can include and dignify the families of same-sex couples, not only for them but for their children, who deserve the same dignity and self-respect that everyone else has.”

Oh, the inevitable Oscar question: Drama actor winner Colin Firth batted down the “Do you think you’ll win the Oscar” chatter with wonderfully British aplomb.

“I am basically just about able to project myself to the end of this press conference. I can’t really get any further than in my mind,” he said.

Natalie Portman stuck with the tried and true. “The greatest honor is just to be mentioned in the same breath (as other kudo contenders),” she said. “It’s just lucky to be in the room.”

The generational divide in how moviegoers have reacted to “The Social Network” has been intriguing to producer Scott Rudin.

“Older people who have been through the experience of starting something” and having things not turn out as expected, “relate to it as a cautionary tale. Younger people look at (Mark) Zuckerberg as a kind of rock star.”

Rudin noted that Zuckerberg and others at Facebook have warmed to the movie, which, he emphasized, does not purport to be a documentary.

“His initial hesitation about it has given way to a genuine understanding of what we were doing,” Rudin said. “They feel it’s been a great thing for the company. More people saw the movie in Japan this weekend than (there are) people who have Facebook in Japan.”

Katey Sagal’s orange frock reflected her glow fresh from her win for FX’s “Sons of Anarchy.” The show is a family affair, as she’s married to creator/exec producer Kurt Sutter.

He’s not been shy about venting his frustrations with the awards season process (and the lack thereof for “Anarchy”). Might her win change his mind? “No!” Sutter shouted from the back of the room. “This honors our show as well as it honors me,” Sagal added quickly.

Steve Buscemi and Kelly Macdonald shared a few giggly whispers as Terence Winter answered for the 10,000th time why he decided to set the show during Prohibition.

Buscemi’s ears perked up when Winter was asked if he’d ever had doubts about Buscemi’s ability to be a leading man. “This is the best job I’ve ever had,” Buscemi said after feigning outrage.

Winter apparently agrees. “If things work out the way I plan we’ll end the series sometime around the Korean War,” he said.

Diane Warren proved to be a class act when one classless journo asked her who she thought was responsible for the murder of Ronni Chasen, Warren’s longtime publicist.

For a split second Warren looked dazed but she kept her composure and deflected the question. She dedicated her win for song “You Haven’t Seen the Last of Me” to Chasen, which was poignant in that Chasen shepherded Warren to the “Burlesque” premiere on the night she was slain. “The saddest thing is that she’s not here to celebrate this with me,” Warren said.

Claire Danes has the aura of low-maintenance star. “Hey guys” she said as she stepped up to the mic. She braved the “what are your beauty tips” and “What was your New Year’s resolution” questions with ease. She spoke with heart about what it meant to her to play Temple Grandin, a woman who overcame autism to notch many achievements.

“It took me a while to commit to another project” after “Grandin,” Danes said. “It’s hard to go to some flat girlfriend role after that.”

Next up for her: playing a bipolar CIA officer in a pilot for a Showtime political thriller, “Homeland.” “I’m having a good time,” she said, noting that lensing has just started. “I hope it’s good.”

Memo to the curators of the Criterion Collection: Robert De Niro is in the market for a megabox set of all of his movies.

The thesp was not overly introspective backstage after being feted with the De Mille Award, but when pressed he noted that he really watches his own pics. But if he catches one on TV he’ll sometimes stick with it. “I’ve thought I’d like to look at all of my movies from the beginning to the present, to get an idea of where I should go after that,” De Niro said.

Paul Giamatti, who was still shaking off the surprise of winning in his category (“If it was me I’d have given it to Depp — He’s a good looking guy.”) meant what he said about falling in love with Montreal, and Canada in general, while making “Barney’s Version.” He wanted to do justice to the beloved Canuck novel by Mordecai Richler.

“It’s so distinctly, uniquely Canadian. I felt a little worried that as an American I might screw up the Canadian national treasure. I was hoping they would not tar and feather me. I won’t work at all if I can’t get back into Canada.”