Heidi Montag Bikini Pictures

Heidi Montag hosted a pool party at the MGM Grand in Las Vegas on Saturday. She wore a sexy bikini for the event, where she posed for pictures with a giant beach ball and got playful with a bottle of champagne and a basket of fruit. Spencer Pratt was also on hand for the festivities, though he let Heidi have the spotlight. Heidi met up with fellow blonde Crystal Harris, who called off her marriage to Hugh Hefner earlier this week. Crystal celebrated in the sun on what would have been her wedding day while Hef screened the movie Runaway Bride at the Playboy Mansion with friends.

Heidi Montag turns 24 today, and boy has she changed since she was introduced to the world on The Hills in 2006! A lot has happened in the past year for the reality star, including the debut of her new body after 10 more plastic surgery procedures, which she has shown off a number of times. Even before her second time under the knife, she hasn't been shy about flaunting her assets — check out Heidi's bikini body through the years!

Heidi Montag returned to LA where she reunited with Spencer Pratt over the weekend, but before she left Costa Rica, she fit in one last bikini photo shoot. She paraded her body on the beach during multiple lonely shoots and even brought her dogs in front of the camera during her time away. In this last ocean romp she picked up a surfboard and donned an unlikely bandeau top, which caused a few wardrobe malfunction close calls in the waves. Quite a way to finish off her Summer full of skin — check it out!

Rihanna and Heidi Montag celebrated the end of Summer by breaking out their bikinis and soaking up the sun. Tom Cruise spent some quality with Suri at a park in NYC and Ben Affleck debuted The Town at the Venice Film Festival, but that's not all that happened this week — click through to see all the biggest stories and best photos!

Heidi Montag wore a purple L*SPACE bikini and went without makeup as she took a solo stroll on the beach in Costa Rica yesterday. She's been living in the Central American country for weeks now and was spotted making a strange dog exchange with her husband Spencer Pratt earlier in the day. The two are said to be working out a puppy custody agreement as part of their alleged divorce. Heidi has spent lots of time in skimpy swimwear showing her sad faces this month. With all the talk of wanting to reduce the size of her breast implants, she's still flaunting her figure in this latest revealing shoot.

Heidi Montag paraded her bikini body around the ocean in Costa Rica last Friday, where she was also spotted hiding out with Spencer Pratt over the weekend. She showed off her bandaged nose during the photo shoot and explained that taping it is part of the healing process as she tries out wearing sunglasses again. Heidi's been open about wanting to get her breast implants reduced, after revealing that her surgery was the reason for the breakup of her marriage, but she still flaunted her enhanced assets in a lacy pink two-piece. Click through for a look at Heidi's bizarre, sad day at the beach.