It's the first 'Rockin' Eve' with just Ryan Seacrest

• Seacrest will host 'New Year's Rockin' Eve' for the first time without the late Dick Clark
• He plans a tribute to the legendary Clark, who hosted the ABC special for four decades
• Taylor Swift will headline the show, which will feature Justin Bieber, Carly Rae Jepsen and Pitbull

The huge New Year's Eve crowd in Times Square always lifts Ryan Seacrest's spirits.

"In a world that has so much chaos and conflict, there's a moment when you look around and you feel as if we're all in it together," he says.

The feeling will be a little more complicated this year. Seacrest will host ABC's Dick Clark's New Year's Rockin' Eve (Monday at 10, live ET/tape delay PT) from New York's Times Square for the first time without Clark, who died in April. The younger host began working on the show in 2005, when Clark returned to the special after having a stroke the previous year.

"It's definitely a mixed emotion. As a kid, I knew New Year's Eve by watching Dick Clark. As an adult, I know New Year's Eve recently by working with Dick Clark. I've never done the ABC show without him," he says."It's emotional, it's reflective, and, at the same time, it's celebratory, because he was such a leader and pioneer and mentor. It will be unique in so many ways, and frankly, I don't know what to expect in that first second when I sign on."

Anne Sweeney, president of Disney/ABC Television Group, says Seacrest is the perfect choice to carry on Clark's four-decade tradition.

"He's injected our New Year's Eve special with incredible energy and talent, but one of the important things to remember about Ryan and New Year's Eve is how he worked with Dick Clark when Dick came back for the first time after his stroke. I think that was a view of Ryan that just endeared him to everyone," she says. "His respect for Dick, the grace and dignity he showed him during the broadcast — I still tear up when I think about it."

The evening kicks off at 8 ET/PT with a two-hour tribute to Clark hosted by Fergie of the Black Eyed Peas and Jenny McCarthy, featuring an appearance by Seacrest.

At 10, Seacrest takes over hosting duties, overseeing a musical lineup that includes Taylor Swift, Carly Rae Jepsen, Neon Trees and Psy in New York. A West Coast party will feature Justin Bieber, Jason Aldean, Pitbull, Karmin, Greyson Chance, Ellie Goulding, The Wanted, Brandy, Flo Rida and OneRepublic. McCarthy will interview those gathered in Times Square, and Fergie will host the Los Angeles festivities.

Swift, who performed on an earlier New Year's Eve show hosted by Clark and Seacrest, is a fitting headliner, Seacrest says. "When we were thinking about this year, we were looking for who was having a bright, bright year and somebody who had been part of the show before," he says. "She was the first choice and a perfect pick."

Swift returns the sentiment regarding Seacrest, the longtime American Idol host and a successful television producer.

"Ryan has become a leader in every business arena he immerses himself in, and someone only gets where he is by approaching every new project with passion and hard work," she says via e-mail. "I'm so excited to be a part of this New Year's Rockin' Eve because I know Ryan throws himself into every part of the creative process to make sure the show is the best it can be."

Seacrest, 38, says he's not certain what he will say on-air regarding Clark, but it will come from the heart and likely not be scripted. He will remember his first year working with the entertainment legend.

"I was so nervous, not necessarily because it was a live telecast, but more because I wanted his approval. ... He'd also had his stroke, so I wanted to make sure I was there for him in every way," he says. "And at the end of it, (you) cross your fingers and hope he pats you on the back and says, 'Not bad, kid. You can do this again next year.' And he did, and that was one of the greatest moments of my life."