CHRISTINA AGUILERA sports em-biggen-ed booty. More junk in the trunk via implant or mere padding?

Xtina wanted to make a booty-ful appear­ance at the “American Music Awards,” so the “Voice” judge padded her prominent posterior.

The “Genie in a Bottle” singer had significantly more junk in her trunk when she walked the red carpet Nov. 18 than she did when she performed later in the evening.

Because big butts are all the rage, Christina wanted to have a bigger behind than fellow pop princess and pal Nicki Minaj, say sources.

Christina has an ample butt, but it’s nowhere near as big as it looked when she first walked into the awards ceremony,” said an observer. “It looked like she had an old-fashioned bustle un­der the back of her dress!”

The shapely, 31-year-old star was radiant with an orange spray-on tan and a tight-fitting purple wraparound dress, split to the thigh.

“Underneath, it was clear she had padding in her panties,” said the source. “She wanted to have a rounder and larger derriere than her friendly rival Nicki, whose behind is so big there have been reports she’s had butt implants.”

At the “AMAs,” the two pals  sported blonde wigs, held hands and hugged for the cameras. But when Chris­tina sang later in the evening, her rounded rump appeared noticeably smaller in a skimpier, more revealing outfit.

“She had a black lace train over her butt, but it was still obvious to everyone that it didn’t stick out so far,” said the source.

Fans and foes quickly reacted to Aguilera’s inflated figure. One critic tweeted: “Christina Aguilera looks like Snooki. No wait, that’s an insult to Snooki.”

Happily, the most important per­son in the singer’s life, boyfriend Matt Rutler, likes Christina’s ample curves,  padded or not. “Matt tells Christina he loves big, beautiful gals,” a close friend told The ENQUIRER.

When the 5-foot-2 Grammy winner recently got blasted for bloating up to 130 pounds, “Matt told her, ‘It’s just more of you to love, baby,’” said the source.

Now she’s up to at least 150, say pals.

But Christina chirped to a report­er: “I’m happy where I am. I have a boyfriend that loves my body, (and) I love my body.”