Michelle Obama has had an eventful few days in New York City.

She set out for the Big Apple right after helping host Chinese President Xi Jinping for a state dinner on Sept. 25, 2015...

Photo by Chip Somodevilla/Getty Images.

So that she could hug Beyoncé on stage at the Global Citizen Festival the very next day...

And then get cozy with Stephen Colbert on "The Late Show" on Sept. 28, 2015.

But the first lady's Big Apple travels, as you may have guessed, weren't just about hanging out with celebs and posting the evidence online (although, would anyone blame her?). She was there to deliver an important message.

Obama was getting the word out about her new #62MillionGirls campaign, which promotes girls' education around the world.

Photo by Justin Tallis/AFP/Getty Images.

The campaign — launched on Sept. 26, 2015, as a part of Obama's broader Let Girls Learn initiative — is focused on helping more girls around the world complete high school by building awareness and investing in existing government initiatives, like the Peace Corps, to prioritize girls' education. Because that 62 million figure represents a sad reality: the number of girls, globally, who lack access to education.

The first lady wrote about why that number is so disproportionately high:

"Many of [those girls] simply can't afford the school fees, or the nearest school is miles away, and they don't have safe transportation to get there, or maybe there's a school nearby, but it doesn't have adequate bathroom facilities for girls. And for many girls, the obstacles they face aren't just about resources, but about cultural norms and traditions that deem girls unworthy of an education."

A key point of the #62MillionGirls campaign is rallying support from the Internet.

Obama has encouraged supporters to share a photo of themselves telling the world what they learned in school.

And the campaign surely hasn't struggled to get support from Hollywood.

Celebs have tweeted out their support in droves (and many used adorable old school pics to do it). Several of them have been retweeted by the first lady.

Here are some of the best ones:

1. Stephen Colbert

2. Kerry Washington

3. Mindy Kaling

4. Charlize Theron

5. Usher Raymond

6. Bellamy Young

7. Chris Martin

8. Leonardo DiCaprio

9. Hilary Swank

10. Dianna Agron

11. Bono

These pics are more than just celebrity eye candy.

(Although, let's get real: Little Mindy Kaling is just beyond cute.) They represent a vital movement that's near and dear to the first lady's heart.

"As I've traveled the world, I have met so many of these girls — and they are so bright, so determined, and so eager to learn," she wrote. "I see myself in these girls. I see my daughters in these girls. These girls are our girls, and I simply cannot walk away from them."

Join the first lady's campaign by tweeting a photo of yourself and sharing what you learned in school using #62MillionGirls.