Scarlett Johansson is insisting on a no-nudity clause in all her movie contracts.The curvaceous 22-year-old is determined to be seen as a serious actress and now won't commit to any role without the clause. A source is quoted by Britain's Daily Express newspaper as saying: "Scarlettis still very young and is aware the roles she takes are going to set out where her career as an actress takes her in the future."She doesn't want to fall into being too controversial or too trashy so nude scenes are out for now."However, Scarlett may have to re-think her naked stance if she lands the role of adult film superstar Jenna Jameson in a movie about her life.The 'Lost In Translation' star has reportedly been singled out by the X-rated actress to play her in a film movie adaptation of her autobiography 'How To Make Love Like A Porn Star: A Cautionary Tale'. Jenna said: "We're looking at Scarlett Johansson. She's my choice. I think she's beautiful."Scarlett is also said to be very keen on the role and is even hoping it could pave the way for Oscar glory.