We have no idea, but Gwynnie is officially teasing our fashion senses with mysterious messages by way of her lifestyle site!
Over the weekend, the actress posted a few teaser pics (below) of the secret collaboration to Goop’s website and Facebook page.
And if you look hard enough, you can see the profiles of Gwyneth and Stella sitting at a table together, but other than that the photos give nothing away.
Thankfully the text gives us a little hint, saying that whatever's going on will launch in September.
We’re preparing for something epic — and expensive.
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