Sienna Miller was snapped leaving a restaurant in London after attending a dinner to celebrate Robert Pattinson\'s 26th birthday. The star looked chic in her grey jumper dress, which showed off her burgeoning baby bump and teamed the outfit with peep-toed ankle boots, a green and brown belt and a huge red bag. She also sported her recently dyed hair, which is now a shade of dirty blonde. But no doubt she had it done professionally this time after she admitted that a self-dye job had gone wrong, and she had to turn to a condiment for help. Speaking to Marie Claire, she said: “I once used henna to dye my hair brown for an audition, thinking I was being clever as it’s all natural. Little did I know it was the worst thing I could have done as it coats the follicles so that nothing else can penetrate so I ended up having to put ketchup in it for about a year to get rid of the green tinge.”