First lady Michelle Obama will tweet for a good cause.

Obama does not have her own Twitter account — she remains one of the few major holdouts of the administration — but on Wednesday, Obama tweeted out a message for Joining Forces, a White House initiative that supports service members and their families.

"So this is how you tweet, huh?" Obama says on the video of the event released by the White House on Thursday evening.

"I did it," she announces after sending out her first tweet, officially denoted by the "-mo" signature included at the end.  

Obama tweeted: "Military families serve our nation too. Let's all show our appreciation by #JoiningForces with them. Get involved: –mo"

The tweet was sent in St. Louis, Mo., ahead of the first game of the World Series. Obama and Dr. Jill Biden attended the game to recognize Major League Baseball's support of the military and military families.

MLB recently worked with Joining Forces on a public service announcement for the program.