Source: Bang Showbiz NewsKristen Stewart has no idea what she looks for in her perfect person but just knew when she met hers.The 22-year-old actress - who recently reunited with her boyfriend of four years Robert Pattinson, 26, after her "momentary indiscretion" with her married 'Snow White and the Huntsman' director Rupert Sanders in August - admitted she isn't sure what she finds attractive but knows when she likes someone.Asked what she looks for in her perfect person, the 'Twilight Saga: Breaking Dawn Part 2' star told Absolute Radio: "I don't know. You just know." The beautiful star - who wowed onlookers at the London premier of her new vampire movie last night (14.11.12) also revealed that if she could go back in time she would tell herself to relax more.She said: "The best advice I've ever gotten is always by example. I would probably just say 'Calm Down' girl. I would say everything's going to be alright, so in case you're ever worried just don't."But the actress recently admitted that the second film in the franchise 'Twilight Saga: New Moon' - which was released in 2009 - is her favourite and she would love to turn back time to film it again.She told the Los Angeles Times newspaper: "It's always been my favourite. I think the depths that are described in that and going from the forest to the bedroom to Italy. Oh my God, that's why you live. If I were to do that movie now.... I really, really, really, really wish I could go back and do that movie again. I would just be better. But I love it and I had a great experience with (director) Chris (Weitz)."