Celebrity Transformations Happy Birthday, Amy Smart Keira Knightley, and Diana Ross! By InStyle Editors InStyle Editors Facebook Instagram Twitter Our editors and writers comprise decades of expertise across the beauty, fashion, lifestyle and wellness spaces in print and digital. We prioritize journalistic integrity, factual accuracy, and also having fun with every story we share. InStyle's editorial guidelines Published on March 26, 2012 @ 01:30PM Pin Share Tweet Email Photo: Tony DiMaio/startraksphoto; Ian West/PA Wire/AbacaUSA; Jeff Vespa/WireImage It's a big day for Hollywood birthdays! Amy Smart celebrated her 36th today, Keira Knightley turned 27, and Diana Ross blew out 68 candles. Congratulations, ladies! To celebrate, we're taking a look back at Keira Knightley's beauty transformation, from breakout Bend It Like Beckham star to glamorous red carpet regular. Click through the gallery to see her best beauty moments. MORE:• Keira Loves Roksanda Ilincic• Keira at the Venice Film Festival• See More Hollywood Transformations!