Ashley Tisdale Shows Off Red Hair at Cosmo's 50th Birthday

Ashley Tisdale and Julianne Hough opt for completely different looks while hitting up Cosmopolitan’s 50th Birthday Celebration at Ysabel on Monday night (October 12) in West Hollywood, Calif.

The ladies were joined on the carpet by singer Cody Simpson, Kingdom‘s Jessica Szohr, and former Miss USA Olivia Culpo.

Scandal‘s Katie Lowes, TV personality Kelly Osbourne, and model Lydia Hearst (with fiance Chris Hardwick) were also in attendance.

“finally heading to south america! just announced shows in peru & mexico this coming january,” Cody later tweeted.

FYI: Julianne is wearing a Femme d’armes shirt, Red Valentino shorts, Stuart Weitzman shoes, Eva Fehren rings, and Sylva & Cie jewels. Ashley is wearing a Signorelli tee and a Maje jacket.

20+ pictures inside of Ashley Tisdale, Julianne Hough, and others at the party…