Stars' changing looks

Actress Evan Rachel Wood arrives at HBO's "True Blood" season 4 premiere on June 21, 2011, in Los Angeles.

The 24-year-old drastically switched up her long, flowing, blonde 'do, chopping off inches for an edgy, pixie cut.(Click the next photo to see an earlier picture of her.)

Atress Evan Rachel Wood attends the "Mildred Pierce" premiere after party at The Plaza Hotel on March 21, 2011, in New York.

Actor Brad Pitt arrives at premiere of "The Tree of Life" on May 24, 2011, in Los Angeles. — Kevin Winter/Getty Images

Brad Pitt arrives at premiere of "The Tree of Life" on May 24, 2011, in Los Angeles.

The actor, who has been sporting a beard on and off for the past two years, showed up clean-shaven at the event. (Click the next photo to see an earlier picture of him.)

Brad Pitt attends "The Tree of Life" photocall during the 64th Cannes Film Festival on May 16, 2011, in Cannes, France.

Blake Lively attends the TIME 100 Gala on April 26, 2011, in New York.

The "Gossip Girl" actress, known for her blonde hair, debuted her new red hair at the event. (Click the next photo to see an earlier picture of her.)

Actress Blake Lively arrives to promote her new film, "Green Lantern" during CinemaCon, March 31, 2011, in Las Vegas.

TV personalities, from left, Kourtney, Khloe and Kim Kardashian pose with their Favorite TV Guilty Pleasure award in the press room during the People's Choice Awards on Wednesday, Jan. 5, 2011, in Los Angeles.

Khloe debuted her new red hair at the event. (Click the next photo to see an earlier picture of her.)

From left, Kourtney Kardashian, Khloe Kardashian (with darker hair) and Kim Kardashian pose backstage at the Beach Bunny Swimwear 2011 fashion show on July 16, 2010, in Miami Beach, Fla.

Keira Knightley poses for photographers prior to Chanel's ready-to-wear spring-summer 2011 fashion show, in Paris, Tuesday, Oct. 5, 2010.

The British actress chopped off her shoulder length hair, fashioning it into a stylish bob. (Click the next photo to see an earlier picture of Knightley.)

British actress Keira Knightley arrives for the world premiere of "The Edge of Love" in Edinburgh, Scotland, Wednesday, June 18, 2008.

Kelly Osbourne arrives at The 8th Annual Teen Vogue Young Hollywood Party at Paramount Studios on Oct. 1, 2010, in Los Angeles.

The TV personality, who has lost a reported 48 pounds since her stint on "Dancing with the Stars," said she cried "tears of joy" after trying on bikinis for a magazine photo shoot. (Click the next photo to see an earlier picture of Osbourne.)

Kelly Osbourne's "Tears of Joy"

Kelly Osbourne arrives for the British Fashion Awards at the Royal Horticultural Halls on November 27, 2007 in London.

British actress Emma Watson walks through Glastonbury Festival, in Glastonbury, England, Friday, June 25, 2010.

On Aug. 5, 2010, Watson posted a picture on her Facebook page showing off a very short pixie haircut. (Click the next photo to see.)

Emma Watson's New Haircut

British actress Emma Watson is seen in a picture posted on her Facebook page on Aug. 5, 2010.

Emma Watson's New Haircut

Kristen Stewart's Dark Hair
Kristen Stewart arrives at the premiere of "The Twilight Saga: Eclipse" on Thursday, June 24, 2010, in Los Angeles.

A few days after the premiere, the actress ditched her long, dark hair for a much shorter, lighter look. (Click the next photo to see.)

Pictures: Kristen Stewart
Pictures: "Eclipse" Hits Hollywood

Kristen Stewart's New 'Do
Kristen Stewart, right, poses with a fan after she talked about her new movie "The Twilight Saga: Eclipse" on the "Today" show, in New York, Tuesday, June 29, 2010. The actress showed off a shorter, redder hairstyle on the show.

Pictures: Kristen Stewart

Janet Jackson's Old Hairstyle
Janet Jackson arrives for the special screening of Tyler Perry's "Why Did I Get Married Too?" on Monday, March 22, 2010, in New York.

The singer shaved off her long locks two months later, unveiling the new haircut during her performance on "American Idol." (Click to the next photo to see.)

Photos: Janet Jackson
Pictures: "American Idol" Finale

Janet Jackson's New Hairdo
Janet Jackson, sporting a short hair style, performs during the "American Idol" finale at the Nokia Theatre in Los Angeles, Wednesday, May 26, 2010.

Pictures: Janet Jackson
Pictures: "American Idol" Finale

50 Cent at 214 Pounds
Curtis "50 Cent" Jackson arrives for the amfAR Cinema Against AIDS benefit at the Hotel du Cap-Eden-Roc, during the 62nd Cannes Film Festival, in Antibes, southern France, Thursday, May 21, 2009.

The musician-turned-movie-star lost more than 50 pounds, dropping from 214 to 160, to portray a cancer patient in the movie "Things Fall Apart." (Click the next photo to see.)

50 Cent Loses 50 Pounds Movie Role

50 Cent at 160 Pounds
Pictures posted on the website ThisIs50.com shows Curtis "50 Cent" Jackson looking incredibly thin. Jackson said he lost the weight with with a liquid diet and three-hour-a-day treadmill walks for nine weeks.

50 Cent Loses 50 Pounds Movie Role

Willia Nelson with Braids
Country music artist Willie Nelson performs during the 57th Annual BMI Country Awards in Nashville, Tenn., on Nov. 10, 2009.

Nelson shocked fans in May 2010 by cutting off his signature long hair. (Click the next photo to see.)

Willie Nelson Chops Off Signature Braids

Willie Nelson's Haircut
Legendary crooner Willie Nelson, right, performs with his son Micah Nelson's band, The Reflectacles, on Saturday, May 22, 2010 at Charley's in Maui, Hawaii. A spokeswoman said Nelson, who's been hanging loose in Hawaii, got his hair cut in the past couple of weeks.

Willie Nelson Chops Off Signature Braids