Amanda Seyfried was dressed to spin in THE GIRLS Tummy Control pants ($30)

Lo Bosworth worked up a serious sweat doing yoga at the Muscle Milk Fitness
Retreat, wearing an Under Armour burnout T and Under Armour Girls’ HeatGear
Capri pants.

Jessica Biel went undercover, hitting the gym in NYC in her Monrow Zip-Up
hoody ($212).

Katy Perry has been spotted numerous time in her PH8 workout gear.

Katy has PH8 workout gear in various styles and colors.

Whitney Port hit the gym in THE GIRLS Tummy Control Pants ($30).