Out N' About: Celebrity Sightings

From Ryan Phillippe's hydration mission to Katy Perry's leather bra birthday surprise, RadarOnline has celebrity sightings from Hollywood and beyond.

Fresh off the Cannes Film Festival, Ryan Phillippe must have hit it hard between travel and swanky parties. The actor was spotted sans girlfriend Abbie Cornish at a CVS in West Hollywood, stocking up on tons of VitaminWater.

Katy Perry was plenty fluid as well, chatting up a storm at a pal's birthday party in Hollywood. At nightspot h.wood, Perry bounced around the room (with security in tow) giving well wishes in a rainbow-colored sequins skirt and a leather bra. Brittany Snow danced with friends nearby.

Someone counting her every friend is embattled Real Housewife Gretchen Rossi, who took some time to smell to roses after dropping charges against an alleged stalker. Rossi was spotted in Palm Springs, CA, enjoying Midori's Sno-Cone launch pool party, alongside Ali Landry and DWTS' Kym Johnson.

A decidedly edgier crowd enjoyed a humble past time across the country in New York City, when the All American Rejects took a break from gigs and album promotion to enjoy some Svedka cocktails at the legendary Bowlmor

(Photo: AP Photo)