Kendra Wilkinson

Check out The Underground’s Web site, and you’ll find nearly endless photos of musicians who’ve dropped by and hopped on the club’s mike; both Kanye and John Mayer visited over the summer. Add to that growing roster Chicago’s own Common, who popped in last Thursday after his concert with Joss Stone at Charter One Pavilion.

It was total chaos when he arrived around midnight. I asked for a quick interview as he shuffled past me, to which he responded, “Let me do my thing first.” His “thing” consisted of sitting on the back of a front-and-center booth, drinking a Belvedere cocktail (the liquor sponsor for the evening), and rapping “Drivin Me Wild,” his new hit single, while Underground owner Billy Dec stayed within arm’s length. Dec has constructed a career around befriending the famous, but I couldn’t help but wonder: What do these celebs get paid for their “impromptu” performances?

“We don’t have to pay fees,” Dec says. “I have been building these relationships on the coasts and in Chicago for over a decade for a reason. In fact, some [musicians] have asked us to play there, as we are doing them a favor.”

Seems like these appearances are more mutually beneficial than favors since they bring a lot of traffic into the club. I must have received 29 e-mails ahead of time promoting Common’s appearance.

Crobar, home of Poparazzi Fridays, has also been hosting celebs on a near-weekly basis. Good Charlotte’s Joel Madden spun in June; since then, the club has snagged Pete Wentz and Ashlee Simpson, Hugh Hefner’s Girl Next Door Kendra Wilkinson, and Entourage’s Kevin Dillon—all of whom have hosted their own birthday parties or simply hung out. “We get people who are not only current but who [patrons] will be excited about,” Crobar owner Joey Vartanian says. “We want to give the public access.” The night of Wilkinson’s appearance, club attendance was 75-percent female, Vartanian says; Wilkinson spent the evening dancing on a bed designed to resemble Hef’s.

Unlike Dec, Vartanian says he pays for the stars. Although he won’t reveal how much each celeb visit has cost him, he says appearances can run anywhere from $1,000 to $50,000—and “That’s not including accommodations,” he says.

“Any time there is a promoted celebrity host, they are 100-percent getting paid,” one insider source tells me—but that doesn’t mean the club is the one forking over the cash. Liquor sponsors often foot the bill, and sometimes other organizations get involved. When Dave Navarro signed a few autographs then sat in a corner all night in May at Manor, sponsor AOL shelled out a cool 25 grand.

Sometimes working with a hot-right-now celeb backfires, as was the case when Desperate Housewives gardener Jesse Metcalfe made a diva-esque stop at Crobar last winter. “That was a nightmare,” Vartanian says. Or when MTV reality star Brody Jenner canceled at the last minute due to a broken arm.

Although last Thursday’s event at The Underground was promoted as a benefit for PAWS and raised about $1,100, Common didn’t mention the animal shelter when he made his shoutout to Chicago. (The event was also promoted as the “official afterparty” for Common’s concert, a title three other venues—including Crobar, where Common popped in before The Underground, Funky Buddha Lounge, and Rednofive—laid claim to.)

As for my interview, I was allowed two questions, which I asked while Common was using the ATM on his way out the door (I guess celebrities really are just like us). On Angelina Jolie, with whom he just finished shooting the film Wanted, Common says: She’s the best. She’s an incredible person; she has a wonderful spirit.” Then he fled, probably off to his next official afterparty.

Shortly after he left, comedian George Lopez, who was in town to perform at the Rosemont Theatre, showed up. When I asked him why he was there, he responded, jokingly, “Because I knew I wouldn’t run into Britney Spears or Lindsay Lohan.”

Not unless they’re getting paid.

For more information on upcoming Poparazzi Fridays, including a party hosted by Kim Kardashian this Friday, visit crobar.com.

Photograph: Tonee Dang