The vixen of high-end mascara is back with its sexiest formula yet.

Lancôme will launch Définicils Precious Cells High Definition Amplifying Mascara this August, with claims that the mascara regenerates the health of lashes through stem cell technology that harnesses Swiss apple extract.

A doe-eyed Julia Roberts is set to star in the ad campaign -- her first product shoot for the beauty brand since signing a contract with them earlier this year.

With a secret pre-sale for the $29 mascara starting today, we expect it to draw a frenzy like Lancôme's vibrating Ôscillation mascara, which had wait lists topping the 21,000 mark.

Lancôme's laboratories closely examined the different follicular structure between lashes and hair on a diverse group of 29 women over a period of nine months. By stimulating lash stem cells with the peptides, lipids and sugars of Swiss apple extract, the study showed an improvement in the structure of lashes.

Plant extracts that are also found in the brand's Absolue Precious Cells skincare line were used for their exceptional abilities to endure harsh environments, and a Madagascan plant known as Madecassoside -- often associated with Ayurvedic medicine -- was added to strengthen lashes. Conditioning arginine was also blended in for hydration.

Like the French beauty brand's best-selling Définicils mascara, its latest version will feature a rich and silky texture derived from a mixture of five waxes meant to coat lashes from root to tip for layerable wear that can go from work appropriate to after hours, dramatic. And the brush will be comprised of short bristles thickly interspersed between longer bristles designed to touch and treat all of the varying lengths of eyelashes.

According to Lancôme, after four weeks of use, more than half a group of 101 women said that their lashes became healthier and stronger, and that they experienced less lash loss when removing eye makeup.

Spring is all about long, thick, sexy lashes. Click here for expert tips on how to get them!