While the hefty application amount shocked followers at first, Willis' explanation was solid. "I do not play when it comes to hyperpigmentation on black skin," she shared via Twitter.
"Our melanocytes are incredibly active and I just don’t believe in taking chances. For sunscreen, in order to get the full protection (you need SPF 30-50), you have to apply enough because that’s how it’s tested in labs."
As for application, Willis says the very fingers you used to measure the amount are your best allies. "Don’t [be] applying sunscreen with a sponge or makeup brush for your initial application," she confirms.
Though her primary recommendation was based on the amount of liquid sunscreen that should be applied to the face and neck, she also offered advice around other areas and formulas.
"[You need] a full shot glass for the body," she explains. "If you’re wearing clothes I don’t think you need to apply underneath for the most part, but obviously everyone‘s body is different so just do your best and lather it on thick."
On the other hand, if you're dealing with a roll-on SPF stick instead of a fluid formula, “four passes back and forth” should do it.
The advice was met with some skepticism at first, with the majority of concern centred around the length of time the sunscreen would take to absorb, and the white or purple cast it would leave against darker skin tones, but Willis was adamant that adequate protection is a cause worth committing to.
"It does not take 30 minutes to rub in sunscreen; it takes me two and after I wait for it to dry (15 mins) I’m [done]. I do my skin first and then get dressed and do my hair [to allow adequate absorption time]. You can also do one finger at a time so you’re not trying to rub in so much at once."
The many followers trying out the technique appeared to apply in the end, with many tweeting their gratitude and glowing reviews for their new go-to application method.