The world’s biggest hair care brand could use some star power. Pantene has tapped actresses Eva Mendes and Naomi Watts to share their hair secrets in TV and print campaigns, scheduled to break throughout July and August. The move ends the brand’s relationship with models because, say company executives, actresses are are more popular, more approachable and more relevant. According to P&G executives, in tests, Mendes emerged “as a strong-willed woman” who garnered high rat...