Britney Spears Bikini Cover PHOTO, Shape Magazine: Songstress Flaunts Tight, Toned Bod in Sexy White Swimsuit, Confirms Las Vegas Residency, 'Slave 4 U' Back in Action?

"It's Britney, b#tch" - and she's back with a sexy splash! Pop star Britney Spears appears on the June cover issue of Shape magazine - and the "Scream and Shout" songstress looks amazing! Flaunting a sexy white bikini, Spears shows off her tight tummy and toned bod - very a la "Slave 4 U" (she even sports the sparkly belly ring!). But do fans really think Spears finally got her killer six-pack back, or did designers have a little too much fun with the airbrush? Either way, she looks great - after working her butt off to get back in shape, Spears is ready to embark on a two year residency in Las Vegas! Read on for more deets.

Spears rocks a skimpy, Deja Soleil cut-out swimsuit on the June cover of Shape. The headline reads - "Britney at her best! 31, firm, and fabulous." And apparently true!

How does this compare to Spears' former sexy looks for Rolling Stone?

Spears (mother of two) admits that it takes hard work to whip her butt back into shape. But she knows it's worth the sweat - especially since she'll be taking up residency in Sin City soon!

"I'm doing 90 minutes of yoga twice a week in addition to a lot of cardio - hour-long sessions three times a week with my trainer," Spears tells the health mag. "The [Vegas] performances won't be simple - they'll be a massive party from start to finish. And to pull this off, I have to be in top condition and running at full speed."

Spears is also following the Nutrisystem diet/weight loss plan... also not so easy - "I like it, then again, I hate it. I'm in my 30s now, so I have to work harder to keep it up. Dieting is tough... because my specialties are spaghetti, brownies and chocolate chip cookies."

But on to the fun stuff... music!

The Las Vegas Sun reports that the former "X-Factor" judge will reside at Planet Hollywood Resort and Casino for two years' worth of shows on alternating weekends in Sin City. Casting for the performances will likely start in LA sometime in late September-early October.

Welcome back, Britney!