By Jennifer Merritt
Jan 13, 2016 @ 5:30 am

With one week to go until the start of her Las Vegas residency "All I Have," Jennifer Lopez is in fighting shape—literally.

"I think of myself as a boxer, and you're training for different things," says InStyle's February cover girl in the video above. "For Vegas, because its going to take so much stamina to do the show, it's going to be lots of cardio, lots of toning, lots of dancing every day in rehearsal, and it'll get me to probably a more fit fighting weight." 

Greg Kadel

Over the course of the hour-and-a-half show, kicking off January 20 at Planet Hollywood, fans can expect to hear a mix of Lopez's hits, many accompanied by a live band, all while she shakes her famous booty in extravagant costumes. So just how will she stay motivated to stay in that fighting shape in a city known for its all-night buffets and endless poolside cocktails? "I get to see myself in a lot of pictures," she says knowingly, "and when you see yourself in a lot of things you go, 'ah, I didn't like the way I look,' 'oh, I need to drop a few pounds,' or 'you look a little tired. [Laughs.]'" (NB to J. Lo: Please show us a picture where you look tired or like you need to lose weight!)

In all seriousness, from what we know about the 46-year-old, there is no external catalyst; it's simply part of Lopez's DNA. "I get motivated by what I have to do," she says. "It's a self-motivation." 

To hear more about Lopez's impressive stamina, plus to see her rehearse for "All I Have," watch the video above, and make plans to catch her Vegas residency at Planet Hollywood's AXIS Theater beginning January 20 (tickets start at $119; To read InStyle's full feature on the mega-talented multi-hyphenate, where she talks about balancing her hectic schedule with being a mom (plus where romance fits into it all), pick up the February issue of InStyle, now available on newsstands and for digital download