First lady Michelle Obama was shaking in her designer shoes as she prepared to tape an episode on Tuesday of the Nickelodeon show iCarly. The title character’s father is a deployed soldier, so Obama’s acting debut is another opportunity to promote the Joining Forces initiative that she and Jill Biden have spearheaded to build national support for military families. Although Obama has delivered a countless number of speeches on this and other issues since her husband first stepped onto the national stage, acting is a whole different bag, she fears.

“I’m going to put on my acting cape. I’ve been memorizing my lines—I’m terrified,” she said at a Joining Forces Entertainment Guilds event. “I can give a speech, I can talk to you all, but oh, I’m shaking, yes.”

iCarly, which stars Miranda Cosgrove, is about a girl named Carly who starts a Web show with her two best friends. In the episode in which Obama appears, the first lady visits the girls after learning that they have broken some rules in an effort to help Carly contact her father on his birthday. It is scheduled to air in January.

“The story line is very sweet,” she said. "They have a Webcast, and Carly is a military kid, and that's always been a part of the script—that’s been a part of their situation,” Obama explained. “Her father has been deployed. And it's just a way for us to recognize her challenges as well as how her friends are stepping up to support her. So I’m pretty excited about it.”

So are Malia and Sasha’s friends, who can’t believe their friends’ mother is going to guest star on one of their favorite shows.

“Let’s say I’m the coolest mom on the face of the planet. Can you believe we have friends of my children who don’t believe that I’m going to be on iCarly?” the first lady laughed. “But I was like, look, I stayed in Buckingham Palace. Why is it such a huge leap?”

Let’s also say that appearing on iCarly isn’t the only thing that makes Obama a cool mama.

(Photo: Michael Buckner/Getty Images)