Britney Spears's memoir, The Woman in Me, is finally out in the world and with it, new revelations about everything from her possible postpartum depression to her relationship with fellow pop star Justin Timberlake. One of the duo's biggest moments came at the 2001 American Music Awards, where they arrived on the red carpet hand-in-hand wearing full denim 'fits. It's become a pop culture touchstone, with Katy Perry spoofing the moment at the 2014 MTV VMAs with Riff Raff and giving fashion fans a reference every time they slip into a Canadian tux.

Spears reflected on the moment in her book, saying that nearly two decades later, she understands that the moment was "tacky" and that she was channeling her Southern upbringing, where "moms love to round up the kids and say, 'Listen, we're going to church today, so we're all going to color-coordinate.'"

When Spears learned that Timberlake was going to wear denim to the show, she suggested, "We should match! Let's do denim-on-denim!"

"At first, honestly, I thought it was a joke," she wrote. "I didn't think my stylist was going to do it, and I never thought Justin was going to do it with me. But they both went all in."

"My corset had me sucked in so tight under my denim gown, I was about to fall over," she said of the look. She even carried a tiny denim bag to the event. "I get that it was tacky — but it was also pretty great in its own way, and I'm also happy to see it parodied as a Halloween costume."

Of course, she had no idea what a cultural impact it would be and even now, she's surprised.

"When he put it on, I thought, 'Whoa! I guess we're really doing this!'" Spears continued. "With the matching denim, we blew it up. I've heard Justin get flak for the look."

"On one podcast where they were teasing him about it, he said, 'You do a lot of things when you're young and in love,'" she added. "And that's exactly right. We were giddy, and those outfits reflected that."