The celebrity co-hosts also share their new year's resolutions and favorite music of 2013

From the rowdiest of all-night parties, to suburban families huddled in their living rooms, millions of viewers will take part in America's most famous New Year's show tomorrow night. The host of ABC's "Dick Clark's New Year's Rockin' Eve" since 2006, Ryan Seacrest knows how the new year brings the people together.

"In a world where people are on different pages all the time, this is the one moment where you feel like everybody's on the same page," he says in a life-affirming tone of voice.

"Unless you're at home living with cats," adds co-host Jenny McCarthy.

On the eve of New Year's Eve, the pair took time from a 15-hour day of preparation to take Billboard behind the scenes of the big night, which kicks off tomorrow (Dec. 31) night at 8 p.m. (ET) on ABC.

"Today we're up to talk to people on television early," Seacrest says. "Then we're gonna go up to the top (of One Times Square) where the 77-foot flagpole is to actually make sure that the ball is there. This afternoon we run through the show -- where we're gonna be, where we're gonna stand, who's performing where, what stage they'll be on, the technical aspects of it."

"It's a good 15-hour day, but we will get cuddle time in," McCarthy jokes. "We'll spend two hours spooning, warming back up."

Behind the 'New Year's Rockin' Eve' Scenes with Producer Barry Adelman

So what's it like to host the big night? Seacrest and McCarthy agree that the cold weather is the biggest challenge, sometimes making speaking difficult when their cheeks become too cold. And the fact that the loud Times Square crowd makes almost impossible to hear someone more than a few feet away certainly complicates things.

Seacrest recalls learning from his New Year's Eve mentor:

"I remember watching Dick [Clark, former host] on television and he had these huge headphones on. I said, 'I don't wanna wear those big headphones.' He said, 'Okay, but you won't be able to hear a thing.' It is so loud that if you were a foot away from somebody you wouldn't be able to hear what they were saying to each other."

The festivities begin at 8 p.m. on ABC with the two-hour “New Year’s Rockin’ Eve Presents the 30 Greatest Women in Music” special. Seacrest and McCarthy's live broadcast from Times Square begins at 10 and lasts through 2 a.m., with a half-hour news break at 11. Miley Cyrus, Blondie, Icona Pop, and Macklemore & Ryan Lewis will perform from New York; when ABC shifts to Los Angeles, performers include Robin Thicke, Enrique Iglesias, and Ariana Grande, with Fergie hosting.

Billy Joel Joins 'Dick Clark New Year's Rockin' Eve'

Miley Cyrus' live Times Square performance figures to grab the most eyeballs, as it's the final one before midnight falls. "I saw a cape," Seacrest says when asked for a preview. "That's all I'm telling you. Will she use this cape or not? We'll have to find out."

Five minutes after midnight, ABC's cameras will jump across the Brooklyn Bridge, giving viewers a live look-in at Billy Joel's Barclays Center performance. ABC's cameras will also grab live footage from Miami, where Pitbull will be performing at the American Airlines Arena.

The celebrity co-hosts were also excited for the "30 Greatest Women in Music" special, which draws from memorable New Year's Eve performances of past decades. Taylor Swift, Whitney Houston, Aretha Franklin, Pat Benatar, and Blondie were all named by Seacrest. "It's hard to believe we stopped at 30. We could do 100 and still not be able to put them all in there," he says.

Watch Daughtry discuss his New Year's Eve performance:

Speaking of amazing women, McCarthy named Billboard's Woman of the Year -- P!nk -- in her year-end favorites.

"'Just Give Me A Reason'," Jenny highlighted. "That song meant so much to me. And I know it's a little bit old. But to me it's the song of the year."

McCarthy says she got her new year's resolution out of the way early, by quitting smoking in December. Seacrest says he's given up on resolutions, though he named newcomers Macklemore and Lorde as his favorite musicians of 2013.