3 Celebs Who Stuck to Their Resolutions

We want to applaud these artists formerly known as train wrecks and give credit to whom - or what - we think helped get them back on track. Still making your list of resolutions? Make 2010 your best relationship and prettiest year ever. Plus: Find out some crazy things celebs said in 2009.

By Katy Lindenmuth

Britney Spears

The Princess of Pop is much, much stronger than yesterday. Follow her comeback. Under strict surveillance from Papa Spears, Brit went from the lowest of lows (think bald, bug-eyed, and brandishing an umbrella at photogs) back to her rightful place atop the entertainment world. The proof is in her current sexy single "3" and ongoing smash world tour, y'all.

Props to: a Cheeto-free diet, gazillions of diehard fans, a new boyfriend who's neither a backup dancer nor a paparazzo

Robert Downey Jr.

A series of drug-related arrests throughout the '90s made RDJ the poster boy for self-destruction and wasted talent. But look at him now: sober, happy, and - not coincidentally - raking in accolades and tons of buzz for his roles in movies like Sherlock Holmes.

Props to: court-ordered rehab, the unstoppable Iron Man franchise, an incredibly dapper wardrobe

Nicole Richie

Just two years ago, this boho starlet was scary-skinny and serving an 82-minute jail sentence for DUI. These days, a healthy-looking (and newly brunette) Nic has two kiddies with longtime BF Joel Madden and a jewelry line named after their daughter, Harlow. She's also developing a sitcom about motherhood, which we think is a much better idea than, say, a sixth season of The Simple Life. Her style has changed too! See her fashion makeover.

Props to: parenthood, increased caloric intake, ditching Paris Hilton

Tell us. Which celeb has inspired you?

Get more Cosmopolitan.com!

5 Girly-Man Trends That Have Got to Go

The New Way to Foreplay

Cosmo's Cleavage Wars

Quiz: Do You Ace a First Date?

The Cosmo Beauty Awards

Reprinted with permission of Hearst Communications, Inc.