LOVE drove Christina Aguilera to lose a whopping 25 pounds!  The 5-foot-2 Grammy winner – who now tips the scales at a healthy 125 pounds – is getting in top shape for her wedding to boyfriend Matthew Rutler, sources told The ENQUIRER.

The “Genie in a Bottle” diva flaunted her stuff March 20 on the season premiere of “The Voice” – dazzling the crowd with her hot new bod and toned-down makeup.

“Christina is sprucing up and losing weight because she and Matt are planning to tie the knot this summer,” revealed an insider.

“She wants a small, at-home affair without too much fuss.

“She decided to give herself a major slim-down as a pre-wedding present, and feels she looks great at 125 pounds.”

To beat the bloat, the perky 32-year-old pop star has been working out five days a week and sticking to a largely fish-and-vegetable diet, revealed the source. “Christina also dialed back her drinking to two days a week, usually the weekend. She has just a glass of wine with dinner.”

As The ENQUIRER revealed last year, the performer’s weight had rocketed to 150 pounds after her five-year marriage to record exec Jordan Batman collapsed in 2010.

The flamboyant, glitter-loving entertainer appeared even heavier because she’d begun padding her posterior to give her more “junk in the trunk” to compete with booty-licious pop stars like Nicki Minaj.

And now that she’s shaped up, she’s ready to be a bride.

Initially, Christina feared that production assistant Matt, her boyfriend of more than two years, was after her $100 million fortune, but she’s finally said yes to his repeated marriage proposals, revealed the insider.

“She’s ready to embark on a new life with a new hot body.”