Credit: Courtesy of Gucci

Oh, babies!

Jennifer Lopez's 2 1/2-year-old twins, Max and Emme, make their modeling debut as the faces of Gucci's new children's line -- and has your first peek.

They appear in the ads along with mom.

"It's the first time I have worked with my kids in that way," Lopez, 40, tells the new Us Weekly (on newsstands now). "It was a totally special experience."

In honor of the collection (with pieces ranging from $80 to $1,600, in stores in November), Gucci donated $1 million to UNICEF's Schools for Africa initiative and $50,000 to Lopez’s charity the Maribel Initiative, which promotes greater access to health care for women and children worldwide.

"It's exactly why I'm excited to be a part of this," says Lopez, who admits she and husband Marc Anthony were hesitant to have their kids participate until they learned of the charity connection. "Now there are two Gucci spokesbabies for a beautiful cause!"

Lopez tells Us the twins "had fun" posing.

"I did a photo shoot when they were 3 weeks old, but now that they are 2 1/2, it’s totally different!" Emme is already showing signs of a fashionista.

Says mom, “Emme picks out her own outfits and likes to sleep in her princess dress." As for her son, Lopez admits, "It’s hard to get Max dressed. He prefers to run around the house with no clothes on."