The One Direction heartthrob and the `Young` singer enjoy hanging out with each other but to avoid being recognised by fans they don disguises and fake accents. Speaking to this month`s We Love Pop magazine about their recent trip to V Festival, Tulisa - who has now dyed her hair brown again - said: "We had such a good time. We were dressed in our hoodies and sunglasses, walking around the crowd. And because we`re both blonde and the same height we pretended to be brother and sister! "The second people walk past and say, `Is that...?" we`d start being really loud, shouting at each other in northern accents like, `What have you done with me ciggies?` or `Pass us that bloody pint, if our mother was here now she`d blooming kill us! Aahh, come on Chez!` "Tom and Chez are our nicknames when we get together and people look at us like, `Oh no, that can`t be them...` because we`re talking in these really loud northern accents. "Now I`ve given it away! We`ll have to change it. Now we`ll pretend to be from Liverpool." Tulisa also revealed how she upset her bosses on `The X Factor` after she changed her back to brunette. The judge said: "I didn`t tell `X Factor`. I thought they knew, but nobody told them, so the opening shots - when we come in on the helicopters - was filmed after the auditions, so my hair was bright blonde. "But I was meant to be brunette going to the auditions so there was this big hoo-ha and I had to wear a wig! "I had `The X Factor` ringing me going, `What have you done with your hair!?` "