Kate Middleton turned 31 in style on Wednesday with a visit to London's Royal Albert Hall to catch a performance of Cirque du Soleil's Kooza. She was joined by her husband, Prince William, and her family including parents Carole and Michael and siblings Pippa and James for the birthday outing. The group sat in the balcony to watch the show. Kate was seen flashing a smile throughout the evening while William cracked a laugh. It was Kate's first public outing in 2013 after she rang in the New Year solo since William was at work performing a helicopter search and rescue. All eyes have been on Kate since she announced her pregnancy last month, and it was recently revealed that if she gives birth to a baby girl, the child will have the title of "princess."