Sideshow: Bit of blowback for NBC

Reassuring news for folks who think gun control laws aren't enforced aggressively enough: They are, when it comes to that most dangerous gang, TV journos. Washington police are investigating NBC's David Gregory for showing off a high-capacity, 30-round gun magazine during a segment on Sunday's Meet the Press.

Gregory, 42, held up the mag, which is illegal in D.C., during a chat with NRA chief Wayne LaPierre. "Now, isn't it possible that if we got rid of these," Gregory said, "isn't it just possible that we could reduce the carnage in a situation like Newtown?" LaPierre wasn't impressed. "I don't believe that's going to make one difference," he said. "There are so many different ways to evade" a ban. The Legal Insurrection blog reported Wednesday that last week, cops denied a request from NBC to show the mag on TV.

The U.S. Senate is in tears this week after a statement by movie star and Argo director Ben Affleck that he won't be joining that wonderful and vital legislative body. "I love Massachusetts and our political process, but I am not running for office," Ben writes on his Facebook page. Ben, who grew up in Cambridge, Mass., was floated as a possible candidate to fill Mass. Sen. John Kerry's seat when the latter left the Senate to become secretary of state.

Why Did I Get Married Too? star Janet Jackson is about to get married for a third time, Us Weekly claims.

The mag says JJ, 46, who previously did the nuptials tango with childhood pal James DeBarge and dancer René Elizondo Jr., is engaged to Wissam Al Mana, a 37-year-old billionaire from Qatar. The couple plan a $20 mil wedding extravaganza, Sources tell Us. (This may be JJ's fourth hub: According to some reports in 2009, she was secretly married for a spell to Jermaine Dupri.)

The heavens smiled on Jessica Simpson this Christmas. The singer and reality star on Tuesday tweeted she and bf Eric Johnson are expecting their second baby. This only eight months after Jess was delivered of her first, Maxwell Drew Johnson. Jess will continue to do ads for Weight Watchers, but is quitting her diet now that she's pregnant. . . . Miranda Cosgrove, former star of nifty Nickelodeon series iCarly, says she was surprised this week with a lovely gift, a new fluffy black-and-white pup named Penelope, People says. Miranda, a freshman at the University of Southern California, lost her beloved 14-year-old poodle, Pearl, in October. . . . Glee creator Ryan Murphy and hub, photographer David Miller, welcomed their first child, Logan Phineas Miller Murphy, born by surrogate, E! News reports. . . . A British watchdog org is investigating BBC severance packages over news that exiting boss George Entwistle pocketed $730,000, twice what he was entitled to. . . . Taylor Swift, 23, tops DoSomething.org's Top 20 Celebs Gone Good list this year. The list celebrates people who do good works and includes Miley Cyrus (No. 2) and Channing Tatum (No. 3). . . . "Gangnam Style," by Korean phenom Psy, has surpassed Justin Bieber's "Baby" to become YouTube's most-watched video ever, with more than 805 million views!

Ready-to-wear fashion and accessories emporium Balenciaga has hired Twilight and Runaways star Kristen Stewart to push its products in exchange for cash and, of course, free goodies.

"I've had four excursions through the store. Isn't that a little bit mind-blowing?" Kristen tells USA Today.

She mimes herself pointing to things and says, "I like that. I like that, too. I've been so [darn] lucky."

That most august institution, Britain's Royal Mail, finally has acknowledged the global importance of The Doctor, that mysterious, millennia-old Time Lord whose good works are celebrated on TV's Doctor Who. In March, the U.K. will release a series of stamps bearing the likeness of the 11 actors who have played The Doctor, including William Hartnell, Jon Pertwee, Tom Baker, and David Tennant. "It's 50 years since a strange old man stepped out of a police box . . . and the most beloved and exciting television series in the universe began," the org says on its website.

Christmas has brought much joy - at least to one beloved institution, Hollywood, with two explosive movie openings. Hugh Jackman musical Les Misérables made $18.2 mil on opening day Tuesday, according to studio estimates. It sets a record for weekday Christmas premieres. Quentin Tarantino's Jamie Foxx-starring Western pastiche Django Unchained made a tidy $15 mil. The two pics have helped the movie industry to its highest-earning year ever, with $10.8 billion in revenue, Hollywood.com said Wednesday.