But it wasn't completely under wraps. Teen Vogue editor Jane Keltner de Valle tweeted a picture of a black-and-white Zoe piece backstage...and pointed out it looked a lot like a frock the stylist used in the mag's October 2007 issue.
So did the mama-to-be copy someone else's work?
Well, sort of.
Turns out the piece from the Teen Vogue shoot was vintage, sourced from the boutique What Goes Around Comes Around in New York City. Rachel loved it so much she bought it and wore it to Marc Jacobs' runway show afterparty that Fashion Week.
And since the Rachel Zoe Collection looks very '70s-inspired, it's no big deal that she borrowed the design, right? It's common for fashion houses to reimagine vintage styles.
What do you think: Is imitation the sincerest form of flattery, or is Rachel's copy job not cool? Weigh in below!