According to the governor's office, attendees will be selcected at random from people who fill out the online application form for the gathering, which will focus on the agenda for the 90-day legislative session that begins the day before.
Takirra Winfield, O'Malley's deputy press secretary, said the exact time and place within the State House are undecided, though the likely location is the second-floor Reception Room.
Winfield said the Democratic governor has been on Twitter for a couple of years but only recently attended a tweetup at the White House, where a group of citizens came in to discuss their views about issues with a deputy press secretary to President Obama.
O'Malley "loved it," Winfield said. "He said I want to do this, so this will be his first and hopefully not his last," she added.
Winfield said the governor hopes to keep the gathering an "intimate" one of about 15-20 people, but she said more might be invited if there's enough interest. She said the staff will make no attempt to pre-screen the group to favor O'Malley supporters. Republicans, she said, are "welcome to join."
By the time a session begins, generally the governor's legislative agenda is largely set, but Winfield said tweetup participants could still have an influence.
"We could get some great ideas we might include or think about," she said. "We're always looking for more ways to connect."
Of course, Twitter purists may object that the O'Malley event -- with it's preregistration form and attendance limit -- isn't a true tweetup but just a Twitter-arranged meet-and-greet. But it's also the rare tweetup that occurs in a building where visitors have to pass through metal detectors to get in. Had the governor wanted the informality of a bona fide tweetup, he might have been better off holding it in an Annapolis bar.