Olivia O'Brien in Bathing Suit is in a "New Era"

Musician Olivia O'Brien describes herself as a "professional oversharer" but her fans don't seem to mind at all. The 22-year-old singer posted photos of herself on social media, wearing a purple bikini with a patterned shirt on top. "I might be in a new era but purple is still my fav color. purpleworld never dies," she captioned the post. How does she stay so fit? Read on to see 5 ways O'Brien stays in shape and the photos that prove they work—and to get beach-ready yourself, don't miss these essential 30 Best-Ever Celebrity Bathing Suit Photos!

O'Brien says she turns into an introvert when rehearsing for a performance. "Prepping for a show is literally just me going into my quiet zone," she says. "That's all there is to it. I have to be in my zone because I'm preparing myself, singing my vocal warmups and I fight off my nerves all day like it's fine, it's fine, and then an hour before the show, I freak out. Usually I have energy after a show, so that's the time I'll want to hang out with my friends. Before I'm like, super introverted. After I'm like, 'Hey, sorry for saying that earlier.'"

O'Brien is passionate about her skincare routine. "I put all my skincare stuff in travel size bottles," she says. "I have a really intensive skin care routine so I make sure I do that every day. I go to an esthetician, so they're all products I get from her. But I do like glycolic acid, aha, benzoyl peroxide. Vitamin C cream is good. Anastasia Brow Wiz and Boy Brow, those are really good but I don't use them every day. Honestly, probably bronzer, just because I need that contour. Randomly, I'll do glitter eyeliner. I'll either be like full glam or look like a boy."

O'Brien tries to stick to a healthy diet while on tour, and loves fruit platters with watermelon and kiwi. "Including kiwi fruit as part of a healthy diet may support your heart health," says registered nutritionist Nicola Shubrook. "This is because consuming them appears to increase high-density lipoprotein (HDL) – the so-called 'good' cholesterol, reduces other blood triglycerides (fats) and reduces platelet aggregation, which may over time lead to atherosclerosis. Kiwi fruit also helps manage blood pressure, thanks in part to a reduction in angiotensin-converting enzyme. Being a useful source of potassium further supports the fruit's heart-friendly properties."

O'Brien likes to keep healthy snack bars on hand while backstage. When choosing a snack bar, choose ones with fiber in them. "Fiber is an important nutrient in a healthy diet," says dietician Samantha Shuflin. "It has many health benefits including helping with digestion, weight loss, lowering cholesterol and lowering the risk of heart disease and diabetes. A healthy snack bar will have 3 or more grams of fiber. If the snack bar has ingredients like fruit, whole grains, seeds, or nuts, it should have no problem reaching this benchmark."

O'Brien is a big fan of vitamin supplements. "I take a lot of vitamins every day," she says. "Sometimes I forget, so I brought one of those old people pill cases, so it's like 'Monday Morning, Monday Noon, Monday Evening.' I'll go to shows and forget that I have my vitamins, there'll be a bag of white pills and they're like, 'What is this?' And I'm like, 'Sorry, it's magnesium.'"