In addition to a Material Girl shop opening inside the Macy's flagship location, the line is available through the department store chain nationwide.
Over the din of hundreds of cheering fans, the elder and younger Ciccone women did their interviews together, continuing each other's sentences like an old married couple.
Here they are on the matter of whether they disagreed while designing the collection.
Madonna: "We didn't have any creative differences, not many..." Lourdes: "But when we did, it was..." Madonna: "We had an arm wrestle, and whoever won, won."
And would they ever release a men's line?
Lourdes (looking excited): "I think so, because..." Madonna: "Material Boy? That's not cool." Lourdes: "Mm."
And -- Mom -- what's the first thing you ever bought at Macy's?
Madonna: "I don't remember." Lourdes: "You probably do." Madonna: "Probably underwear."
"She did most of the work, I just hung out in the background," Madonna said of Lourdes. The resulting teen collection features affordable items from shoes to dresses to accessories, which Lourdes said were inspired by her mother's iconic fashion.
"Oh my God, like, absolutely," she said. "There's some definite pieces, like the tulle skirt. That was, like, her thing. The necklaces, the gloves, the lace tights, the combat boots with the skirts. It's tough [and] girly."
As for other inspirations, Lourdes said: "I think Taylor Momsen has great style..." Madonna: "You love Lady Gaga." Lourdes: "Yeah, Lady Gaga."
Momsen, who is featured as the face of the line, told us: "It was such an honor to be chosen by Madonna and Lola. Madonna is the original Material Girl. She's the one who did it for herself and did it to the fullest and -- without using profanity -- she said, 'This is who I am, and this is who I'm going to be' and she stuck to that all through her reinventions.
"And this line really reflects that."
In related news, check out Victoria Beckham's Spring 2011 dress collection.