"Dancing With the Stars" premiered in June 2005 as a quick, six-week series — who knew it would become a phenomenon? Certainly not host Tom Bergeron.

"I thought it would be fun, but I didn't think it would be anything more than a summer show," Bergeron said during an interview in Washington earlier this summer. "So I've been happy to be wrong about this one."

More than a decade later, Season 23 of the ABC competition series debuts Monday night. Although it airs only once a week now, instead of twice, and although about 13 million people watched per week last season, instead of its heyday of 20 million in 2011, the show is an undeniable pop culture force. So it's surprising to Bergeron that even though celebrities must know the deal by now (the show is a great-but-physically-grueling career move), some participants are still naive about the process.

"It's interesting to me, given all the years we've been on, how many of them are still stunned a few weeks in about how much is required to be really competitive in terms of learning the dance steps," said Bergeron, who co-hosts with sportscaster Erin Andrews. "And the deeper you are into the run, the more likely that you have to learn multiple dances for the competition as it gets into the quarters, semis and finals. But a lot of them are like, [high pitched voice] 'Whaaaaat?'"

This year's cast should prove especially entertaining, or a trainwreck — the latter is always ideal in reality TV, of course. Notable contestants include former Texas governor Rick Perry (R), coming off his second unsuccessful presidential campaign; Laurie Hernandez, the 16-year-old gold-medal-winning U.S. gymnast; Amber Rose, the model and TV personality; and Ryan Lochte, the scandal-plagued swimmer who caused an international incident when he lied about details of a robbery during the Summer Games.

Lochte, though a polarizing figure, has a shot: Athletes, especially NFL stars, always do well in the competition. (Former Detroit Lions wide receiver Calvin Johnson is also part of the cast.) Bergeron confirms that athletes certainly have an advantage on the show.

"They are more likely to be less ego-focused on being criticized because of their familiarity with being coached — they don't take it personally as much," he said. "If you're dealing with performers who are used to having a little cadre of 'yes people' around them, the whole concept of 'you've got to learn this because it's going to be hard and you've got to practice it' can sometimes be a little foreign."

In the meantime, Bergeron — who has been nominated for the reality show host Emmy award every year since the category was founded in 2008 — says he'll keep hosting as long as the show keeps going; he's under contract for three more years. Though the show is a well-oiled machine at this point, Bergeron still welcomes surprises, such as being delighted by contestants he would never expect.

"Going back to an earlier season, when they booked Jerry Springer [in 2006]. I thought 'Really? Jerry Springer?' I'd seen his show," Bergeron said. Then you meet him, and he's a total sweetheart, and a mensch, and I love the guy. So there are surprises like that."

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