For many, Jennifer Lopez already has the perfect body — but the singer still sees room for improvement. Especially when it comes to how she's going to look at her upcoming wedding to Alex Rodriguez.

J.Lo is planning to marry her boyfriend of nearly one year in the spring and sources reveal exclusively to Life & Style that the 48-year-old has been taking the phrase "shedding for the wedding" to a whole new level. "She's been working out at least five days a week," says a source before adding that she has hired a nutritionist and personal trainer.

So, how is the mother-of-two getting in shape? According to the insider, she is toning her famous booty with "tough cardio workouts, yoga, running, cycling, boxing, and dancing" and guzzling lots of water. And she's not alone. A-Rod is also joining her in the gym.

Recently, the former Yankees star shared a video with Jennifer as they worked out together, captioning the clip, "2018, here we come." Last month, Life & Style reported that Alex, 42, was preparing to pop the question and has already purchased a diamond big enough to impress Jenny from the block. “A-Rod dropped $3 million on a custom 15-carat diamond engagement ring,” the source said. Though he didn’t consult her about it, “he knows her style,” the insider added. “Big stone, lots of little bling on the band.”

The source continued, “He wants to start the New Year knowing Jennifer will be his wife. He didn’t have to do it, but A-Rod asked Jen’s mom [Guadalupe] and dad [David] for permission to marry their daughter. Of course, they said yes.”

And despite her intense wedding boot camp, Alex thinks his bride-to-be looks perfect. "A-Rod loves J.Lo's curves," the source notes, "and is always telling her how incredible she looks." Let's hope fourth time's the charm!

For more exclusive celebrity news, be sure to pick up the latest issue of Life & Style on newsstands now!