Kate Upton has admitted "being make-up-free stands for loving myself".

The 28-year-old model-and-actress has admitted it was "nerve-wracking" going bare-faced for PEOPLE's Beautiful Issue as she battled with melasma, a skin discolouration, when she was pregnant with her daughter Genevieve, who is now two.

She said: "Of course, the first bit of melasma was right over my upper lip, which made me look like I had a permanent moustache. [My skin's] reaction to being in the sun changed a lot."

The 'Layover' star also opened up about the "negative" impact social media has on the relationship people have with themselves and insisted applying make-up should be about making oneself feel "better" about themselves.

Kate continued: "I feel like make-up is so nice if you use it in a way that makes you feel better about yourself. But there are also so many times when you're putting on make-up to cover up or change different ways of your face.

"I see it more and more with social media. It creates a negative mental relationship with yourself that you feel you should change. So I think being make-up-free stands for loving myself how I am. Although I do love make-up, I appreciate what being make-up-free means."

Asked when she feels most beautiful, Kate told the 'PEOPLE Every Day' podcast: "It's always a journey because we're human. You feel stressed some days and you feel overwhelmed or tired. I think just going back to appreciate the connections we have — the family, the friends and putting how I feel beautiful on my relationships and on my relationship with myself. [That] is how I feel most beautiful."

As for her skincare routine, the Sports Illustrated cover star revealed she uses "cooling" products and LED light masks on her sensitive skin.

She said: "It's hard with the sun. I have such sensitive skin that suddenly I'm always red. So anything cooling is nice.

"I've been very into LED light masks. It's helping even my skin tone, because like I mentioned, the melasma.

"I love face masks because sometimes you'll see even the simple change of your complexion.

"I have a great ice roller that I love to use to bring down puffiness. There are little things you can do to make yourself feel more confident."