Earlier this year, the producers of “Dancing With the Stars” asked PBS host and political commentator Tavis Smiley whether he would consider being a contestant on the popular reality competition series. Almost immediately, he said no. They asked again. He declined again.

Eventually, they asked once more. This time, Smiley, who has been called “one the most important political voices of his generation,” pulled out a notepad to make a pros-and-cons list.

“To my surprise – to my horror – the many reasons to do this far outweighed the reasons not to. I was stunned by that,” Smiley said in a phone interview from Los Angeles on Thursday, mere hours after he was announced as a contestant on the upcoming 19th season. “That would not have been the case years ago.”

That’s because Smiley was busy establishing himself as a brand, and a serious one: PBS talk show, NPR radio host, bestselling author, commentator, head of a charitable foundation. Besides, people who interview top political figures and regularly appear on Sunday Beltway shows can’t don sparkly costumes to do the rumba on national television and compete for something called a “Mirror Ball Trophy” – right?

Except that Smiley’s doing just that, already deep into rehearsals with his professional dance partner, Sharna Burgess, before the season premiere kicks on Sept. 15. He’s seen enough research on his personal image to know this is the last thing people would expect him to do. And that’s what makes it appealing – plus the fact that he wanted to do one more “foolish” thing before he turns 50 this month. It’s also an unusual choice for the show, which often casts reality stars and nostalgia actors hoping to make a comeback.

Sure enough, Smiley’s phone was buzzing all day with calls and e-mails – he didn’t tell his family in advance (he has nine siblings), and he says they’re somewhere between shocked and ecstatic. He’s also looking forward to showing off another element of his personality to fans who have known him for years from television and public radio and might not know how much he loves things like comedy, sports and music.

“People know some of me, but they don’t know the sum of me,” he said of his toned-down on-camera reputation. “I think that this experience will let people see the other part of me. And not just the audience – I’m going to learn some things about myself.”

What also makes this experience particularly special is that Smiley grew up in a very strict, religious household and wasn’t allowed to dance or listen to music; when he was class president his junior and senior years of high school, he was forced to skip prom. Although he missed out on years of dance practice, he’s going to be forced to catch up in a hurry.

That’s going to be one of many challenges, especially since Smiley still has to record his TV and radio shows. Not to mention he’s already locked into a national tour this fall to promote his latest book, “Death of a King: The Real Story of Dr. Martin Luther King Jr.’s Final Year.” Burgess will travel with him around the country so that after he’s done with his book signings, they can practice dance routines until about 2 a.m. Then, it’s back to Los Angeles each week for the live show.

Of course, that depends on how long Smiley sticks around – the judges’ and audience’s votes are combined, and the contestant with the lowest score is sent home. Smiley thinks the producers chose him for the “shock factor,” since no one would expect him to be on the show. That alone could be enough to get him through a few weeks, as that element had a similar effect with HLN TV personality Nancy Grace in Season 13. “I must be the Nancy Grace of this season,” Smiley joked.

Is Smiley worried that his political guests won’t take him seriously after watching him groove on prime-time TV? (“I’m used to seeing you Sunday morning, I didn’t know you could dance,” “Good Morning America” co-host and “This Week” anchor George Stephanopoulos said during the cast announcement on Thursday.)

Smiley isn’t worried. He said, “I don’t think, at this point in my career, that I have to worry about that.”