Three weeks ago, 257 young girls were kidnapped from their school in eastern Nigeria.
Since then, thousands of Twitter followers have joined the campaign to have the girls safely returned to their homes, making the hashtag "BringBackOurGirls a worldwide trending topic.
Now the movement has its most powerful follower to date, as Michelle Obama has joined the fight.
The First Lady tweeted the above photo recently, along with the caption, "Our prayers are with the missing Nigerian girls and their families."
Michelle Obama joined Instagram last year and has spoken publicly about the important role played by social media in activist and grass roots political campaigns.