The Huffington Post today chronicles the amazing story of how UCB comedian Chris Gethard managed to get Sean “Diddy” Combs to appear on his improv show last Friday night after a year-long campaign from Gethard and his fans.

I’d recommend reading the whole story, which is well told by HuffPo “comedy intern” Ross Luippold, but here’s an excerpt:

The evening was the culmination of a 13-month Internet campaign to get Diddy to appear in The Chris Gethard Show, a freewheeling talk/comedy show that touts itself as “the most bizarre and often saddest talk show in New York City.” Gethard began his personal mission of getting Diddy to appear on his monthly show on Christmas Eve 2009, in the form of a YouTube video of a personal plea to Diddy to appear on the show.

“I want to live in a world where I can make a video like this, and you’ll somehow see it,” Gethard said in the video, addressing Diddy. “And you’ll come and make an appearance on my show. Even if that appearance is thirty seconds long.”

Gethard encouraged his followers to use the Twitter hashtag #diddygethard — the logical way to reach the rapper, whose Twitter account, @iamdiddy, boasts over three million followers and is updated with remarkable frequency. Within days of posting his video, Gethard was on the phone with Diddy explaining the barrage of #diddygethard tweets. (Gethard’s last name rhymes with “tethered,” which clears up a more unseemly interpretation of the hashtag.)

“Twitter is weird,” Baer said. “This show could not have happened three years ago. Three years ago, Gethard might have said, ‘Who knows how to contact Diddy? I would like to get Diddy on my show.’ And people would have said, ‘Maybe? No! How would you do that?’ But now you can.”

Soon, Gethard reached an even larger audience to promote this idea that was slowly turning into a reality. During an appearance on “Late Night with Jimmy Fallon” to promote “Big Lake,” Gethard spoke at length about his intent to book Diddy on his show using Twitter. That night, #diddygethard was a Trending Topic in New York City. Now that the campaign had gained enough traction, the comedian approached Diddy backstage at “SNL,” where Diddy formally promised, on camera, that he would appear as a guest on The Chris Gethard Show. Soon after, the show was officially booked for January 14th, 2010.

Here’s a look at Gethard’s original YouTube video plea for Diddy, and his Jimmy Fallon appearance: