Country singer and Grand Ole Opry member Kelsea Ballerini just celebrated her birthday. And she did so in a bikini. Ballerini posted a photo on Instagram of her wearing a yellow bikini while enjoying time on a yacht. How does she stay so fit while keeping so busy? Read on to see 5 ways Kelsea Ballerini 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 Bikini Photos!

While Ballerini isn't a vegetarian, her husband, singer Morgan Evans, is. Ballerini tells Shape, "My husband, who's from Australia, is a vegetarian. I grew up on chicken nuggets and waffles, so trying to match that was really interesting." Ballerini says the solution is cooking a lot of vegetarian meals. "We cook a lot of lentil Bolognese, or we'll do Mexican bowls with tempeh instead of chorizo. I've found a good groove with healthy meatless alternatives for some of our favorite stuff, which is fun. When we go out, I'll get my fix of whatever I'm craving." Ballerini says the COVID-19 pandemic made her fall in love with cooking. "I was never a cook. I was never home, so I never cared to. But I fell in love with it this past year."df44d9eab23ea271ddde7545ae2c09ec

Ballerini tells Shape that while she doesn't follow a specific diet, she follows the 80/20 rule. Ballerini says this plan helps her feel balanced. "I've always been an 80/20 person as far as food and drinking. I try to do what's good for me 80 percent of the time. The other 20 percent of the time, I just enjoy my life. I run through the McDonald's drive-through once a month, and it's fine. Sometimes I'll have a little too much wine, and that's OK too. I've spent so much of my life feeling guilty for things that I eat or having an unhealthy relationship with food or the gym or whatever. So I just try to be nice to myself and do what's good for me. And when I don't, I start again the next day."

Ballerini tells Shape that she and her trainer strength train, even during the pandemic. "I've worked out with my trainer, Erin Oprea, for five years," she says. "We're on Zoom three days a week and do a lot of strength training intervals, where you alternate two exercises until you've burned that muscle group, then move on. We cram it all into 45 minutes and call it a day."

Ballerini admits to Health.com that she used to feel bad about eating healthfully. "I definitely went through a phase of shaming myself if I ate something 'bad,'" she says. But she has learned to find balance in her food and indulges once in a while. "I will never not have chicken nuggets in my life—or a few glasses of wine. I don't ever want to feel guilty for having those things in my life."

According to Ballerini's trainer, Erin Oprea, the singer doesn't exercise to lose weight, she does it to be healthy. "Kelsea came to me simply wanting to better her overall health and make [fitness] a lifestyle habit, and she's doing that at a young age, and I admire that so much," Opera says to Health.com. The singer also tries to have fun when she works out. "She also wanted to learn how to make exercise fun and not a chore," Oprea says. "So that's what we do—we turn on the Nelly radio and we make it fun."