BEST: Pippa Middleton can do no wrong when it comes to casual summer fashion. Her royal hotness’ nude maxi dress and cropped white jacket combo was a winner for a trip to a salon in the posh London neighborhood of Chelsea on Monday.

WORST: Someone needs to tell Vanessa Hudgens that a baggy shirt and boots makes a hot mess, not a hot summer fashion trend. The former High School Musical star looked like she’d forgotten her pants when she went shopping in Studio City, CA on Monday. We really hope she bought some new clothes on her trip to the shops.

BEST: Oscar-winner Helen Mirren looked like real royalty in a crimson long sleeve asymmetric draped dress from the Michael Kors Pre-Fall 2011 collection to a screening of The Debt in New York City on Monday.

WORST: Kirsten Dunst has always been known for her off-the-wall sense of style, which has gone from grungy to grandma over recent years. This floral shirt and fitted skirt make her look like she’s heading to secretary school instead of a movie screening of My Idiot Brother in Times Square.

WORST: Was Olivia Palermo planning to skydive into the screening of My Idiot Brother? Having leapt to the red carpet from a plane would be the only excuse for the NYC socialite to wear a shiny jumpsuit for the star-studded premiere.

BEST: Sports Illustrated model Irina Shayk slinked onto the red carpet for the My Idiot Brother screening in a sequined halter neck mini dress and sky-high red heels that perfectly showed off the gorgeous Russian’s tanned 5’10” figure.

WORST: Were Khloe Kardashian and husband Lamar Odom suffering from a fashion hangover? After a whirlwind wedding week for sister Kim, Khloe seemed relieved to swap her Vera Wang bridesmaid dress for a sloppy striped hoodie.

BEST: Knowing that all eyes are still going to be on her even though the wedding is over, Kim Kardashian was glamorous in a draping beige dress when she jetted off from LAX for a quick honeymoon. Of course, the new Mrs. Kris Humphries’ best accessory was her gorgeous new husband on her arm!

Worst: The only thing more colorful than the busy back-drop behind her was Kelly Osbourne’s kaleidoscopic dress at the God Bless Ozzy Osbourne premiere in Hollywood. The padded shoulders, shiny fabric and clashing patterns were enough to give anyone a headache, but the reality star appeared to be delighted with her daring fashion choice.

BEST: Zoe Saldana turned up the heat to tropical extremes on Monday when she wore a glittering Balmain Resort 2012 gold embroidered mini dress with a flowing white train for the Colombiana screening, which made her look even more exotic than ever.