Kristen Stewart's real-life relationship with Robert Pattinson helped her portray his on-screen love interest in the 'Twilight Saga.The 22-year-old actress revealed she found it easy to play Bella Swan, who is hopelessly in love with Robert's vampire character Edward Cullen, because she has experienced that overwhelming love in real life. She told 'Entertainment Tonight': ''I know what it's like to love something so much.'' The couple recently reconciled after Robert, 26, forgave Kristen for cheating on him with married director Rupert Sanders and Robert confessed shooting the intimate sex scenes for the vampire movie was not easy because they had to look sexy while still making the movie suitable for a younger audience. Speaking about the scene in 'Twilight Saga: Break Dawn - Part 2', Robert said: ''The sex scene in this one is pretty ridiculous as well, you're shooting stuff to be PG, you're trying to think of things to make it sexy, it's supposed to be about the greatest vampire sex you've ever had. You try and give a face of ecstasy; guy's faces I don't think are really designed to do that.''