The former Destiny's Child star, Lovato and actresses Olivia Munn, Jordana Brewster, Famke Janssen and Morena Baccarin have all dared to be bare in the spread as part of the publication's efforts to show off natural beauty - and Rowland insists it was a nice to pose without make-up.
She says, "I started wearing makeup at 14 for Destiny's Child. I remember the first time I saw my lashes with mascara on them - it was my favourite thing. For me, make-up reminds me of work. Without it, I feel natural and untouched."
The X Factor judge Lovato enjoyed the experience too, adding, "Anytime I can get away with wearing no make-up, I do it. But when it's showtime, I rock it up."
And former Bond girl Janssen thinks she actually looks better without make-up, insisting, "I'll wear eyeliner or a little big of eye shadow, but less is definitely more for me, because I'm angular and my features are strong already."
However, 33-year-old Homeland star Baccarin confesses the idea was a little unnerving for a woman her age: "It's vulnerable and scary, but I love the challenge of being comfortable without make-up. I wash my face every morning and night. I put on a moisturiser, toner and eye-cream all-in-one, and I walk out, that's it."