It’s been 14 years since she played Rachel Green, but it seems 49-year-old Jennifer Aniston hasnt aged a bit post-

“I feel fantastic,” the star, who turns 50 (!!) in February, told Ellen. Part of the reason: She’s been boxing with her trainer , co-owner  in Los Angeles, who Jennifer described as her “gentle giant.”

“He calls me ‘champ,’ and it’s not weird!” Jennifer said of her trainer, adding, “I never thought someone would be able to call me champ and I would be okay [with it]. ‘Hey champ! We gotta get [your heart rate] up to 80, champ!’”

And Azubuike confirmed that Jen is a total badass in the gym. “She’s very diligent. She is ready to work out hard, every single time she hits the gym,” he told People. “Whether it be a 45-minute session, whether it be a two-hour session, she’s always ready to go. Incredibly consistent and hardworking, and that makes my job a little bit easier. She’s a very good, natural athlete.”

Jennifer is definitely on the boxing bandwagon. "It’s the longest workout I’ve actually stayed with consistently other than yoga," she told In Style for their September cover story. “There’s something about the mental aspect of boxing-the drills, your brain has to work, you’re not just sitting on a bike. It’s amazing.”

In 2016, when Jennifer graced the cover as People's Most Beautiful Woman, she revealed that she works out for about an hour each day, and usually rests on Sundays. Being consistent is key, she said, even when you really don’t feel like working out.

Jennifer is able to stick to her routine, in part, because she switches things up. "Three days a week I'll do a spin-yoga class, which is 25 to 30 minutes of spinning and then 30 to 40 minutes of yoga,” she said. "You have to shake it up-you know, muscle confusion." And it appears boxing has made it's way into her rotation this year, too.

As for her enviable arms, the celeb shared a little secret for keeping them toned: yoga and lifting her own body weight. “When I'm at the gym, there are the ropes,” she told People. “Grab little five-pound weights if you have nothing else, and just move them around."

For fuel, Jennifer loves sipping a fruit-filled smoothie made with “bananas, cherries, blackberries, a greens powder, a collagen peptide, a little cacao powder, chocolate stevia drops, and chocolate almond milk,” reports People. “You can see I like chocolate-flavored. I don't like protein taste."

Whatever she's doing, it seems to be working.