With her oversized sunglasses, scrapped back hair and thrown together outfit, Jessica Alba could easily be mistaken for Britney Spears.The pregnant actress, 26, ditched her usual designer wardrobe for a low-key combination of jeans, sundress and flip-flops – a familiar staple of Spears’ wardrobe – for a busy day in Los Angeles.Alba, who is expecting her first child in June, opted for laid-back comfort as she shopped in West Hollywood, before visiting her doctor.