Twilight stars Kristen Stewart Robert Pattinson and Taylor Lautner have cemented their places in movie history after taking part in a hand and footprint ceremony outside Hollywood's famous Grauman's Chinese Theatre.The actors got down and dirty to sink their hands and feet into wet cement on Thursday as hundreds of screaming fans cheered them on on Hollywood Boulevard.Twilight author Stephenie Meyer and comedian Jimmy Kimmel were on hand to introduce the trio to the crowds, which included the young stars' parents.The importance of the honour wasn't lost on the actors - a stunned Stewart gasped, "This is insane that I'm doing this", while Lautner struggled to find the words to describe the big moment.He said, "There are a few moments that mean so much, it's really even hard to explain."And Pattinson added, "This is incredibly scary... This is such an incredible honour. How young we are? It's kind of ridiculous and amazing at the same time."Earlier in the day, Stewart was spotted arriving at Los Angeles International Airport with a plastic cast supporting her right hand and wrist, but the new medical accessory was nowhere in sight when she appeared on Hollywood Boulevard.Stewart was fitted with the cast last month after falling off a horse and injuring her wrist and ankle while filming upcoming fantasy movie Snow White and the Huntsman