Charlotte Tilbury Just Spilled the Beans on Blake Lively's Best Beauty Secret

Blake Lively looked extra glamorous on the red carpet at the Cannes Film Festival in early May — and now we know why. As a face of L'Oréal Paris and a star of the festival's opening-night film, Café Society, Blake has had gorgeous dresses and Charlotte Tilbury's makeup skills to look utterly gorgeous.

Charlotte, however, spilled the beans on one of Blake's best beauty secrets when she posted a behind-the-scenes snap of their time together. "Thank you Blake," Charlotte wrote, "for introducing me to the best kept secret: @themakeuplight. It's changed my life!"

So what, exactly, is this gadget that surprised even a beauty guru on the level of Charlotte Tilbury? The Makeup Light, which is available online, is a portable LED light stand that purportedly mimics daytime sun inside. Because it's easy to pack up and take on the road, it's understandable why someone like Blake — who jets from event to event regularly — would fall in love with such a gadget. With the Makeup Light, Charlotte and Blake can see how a full face of makeup looks in the hot sun and before a sea of flashbulbs.

But, of course, such a tool doesn't come cheap. The Makeup Light's starter package is priced at $360 — and go up to $1,299.