ALEXANDRIA, Va. - First Lady Michelle Obama may have reluctantly embraced her very public role in the White House, but today she clearly relished the TV stardom that has come with it.

A beaming Mrs. Obama burst on stage to a celebrity-style welcome from 1,500 screaming youngsters in a school auditorium here for the premier of a new episode of Nickelodeon's "iCarly" that features her.

The cameo and screening were billed as part of Mrs. Obama's Joining Forces initiative, which raises awareness about the need to support U.S. military families.

In "iMeet the First Lady" - which airs nationwide on Monday - Mrs. Obama plays herself, paying an unexpected visit to Carly Shay, the show's lead character, who's struggling to cope with her father's continued deployment in the Air Force overseas.

"So what are you doing here, your excellency?" a surprised Shay exclaims.

"You don't call her 'your excellency,'" interjects her brother, Spencer.

"I kind of like it," replies Obama with a smile.

"I'm here to say I'm proud of you," she then adds with seriousness. "It can be really rough for kids who have a mom or dad way from home for a long time."

Mrs. Obama later tells Shay and her friends, "As important as it is for Carly to support what her dad is doing, it's just as important that she has good friends like you who support what she's doing, too."

The highlight of Mrs. Obama's appearance was her participation in "random dancing" with the characters, which she reprised live on stage today in what turned into a dance party scene.

The first lady later told the audience that she regularly watches iCarly with her daughters and saw appearing in the show as a good opportunity to reach a new audience.

"We did this episode because we want the country to know how proud we are of all of you," she told the children of military parents in the crowd. "Know that you have an entire country that stands behind you guys, ok?"

During a Q&A period, she told the kids that if she could have any super power, she'd want to be able to fly and that her favorite room in the White House is the yellow oval room because it connects to the Truman balcony where she and her husband can sit outside.

Mrs. Obama drew light grumbles over her response to a student request that she help improve school lunches at Hayfield Secondary School.

"You should be seeing more vegetables, more fruit, more healthy foods" in school cafeterias, she said, touting her efforts on nutrition.

"It's hard to do what you do if you're not healthy and you're not eating right, and you're not putting good foods in your body, you're not getting exercise.  And so we care very much that you start learning those habits early," she added.

"And eat your vegetables!"