We've heard this saying time and again: Mom knows best. And that's because she really does. Secret hacks? She holds them. Inspiring advice? She has it. Comfortable shoes? Oh you bet she owns them.

So it's no wonder that so many moms in Hollywood, like Hilary Duff, Reese Witherspoon, Katie Holmes, Chrissy Teigen, Naomi Watts, and Mandy Moore, have been wearing their tried-and-true Birkenstocks — for everything from school drop offs and quick grocery runs to coffee breaks in between playdates — for years. 

Buy It! Birkenstock Narrow Arizona Birkobuc Sandal, $79.99 (orig. $99.95), gilt.com

The beloved Birkenstocks certainly have range, so the brand's three-digit price tags are definitely worth it. But we're always on the hunt for a discounted pair, because who wants to pay full price? And luckily, we found a secret Birkenstock sale at member-only site Gilt that's happening for just 48 hours.

Don't let the "member-only" part scare you off. It's 100 percent free to join Gilt: All you have to do is sign up with your email, and you'll have access to thousands of exclusive offers, the latest (and perhaps greatest) being this two-day Birkenstock extravaganza.

It seems like almost every Hollywood mom owns some variation of the Arizona sandal, the brand's signature two-buckle slide that has a super supportive cork footbed. The style usually costs between $100 and $150, depending on whether you go with the real-leather sandal or the Birko-Flor option (a durable leather alternative), but right now, Gilt has both starting at $80. 

Other Birkenstock sandals on sale at Gilt that are 100 percent worth scooping up include that beloved Boston Clog that Duff favors, especially when she's running errands, and the T-strap Gizeh slide that Sienna Miller seems to wear nonstop. 

With warm weather around the corner and comfy shoes as in demand as ever, we have an inkling that styles will sell out fast. So head on over to Gilt and snag a pair while you can!