Source: Bang Showbiz NewsNicole Scherzinger wouldn't wish a long-distance relationship "on anyone".The 'Poison' singer has been dating British racing driver Lewis Hamilton on and off since 2007, and while she admits it can sometimes be tough, she thinks it is worth fighting for.She said: "Every relationship has its things and you work it out. We made it last for four years so far, so it definitely makes things interesting and a challenge."I wouldn't wish a long-distance relationship on anyone, Lewis would say the same. But if it's worth it, you fight for it. We try to see each other as much as possible."Lewis has also made appearances backstage at the UK 'X Factor', where Nicole is currently a mentor.She said: "Lewis was backstage. He enjoys it and is supportive of me."I don't care whether he thinks he was dragged there! He wants to support me - I am there for him and his races."She also denies anything unsavoury ever happened between her and Chris Brown, after they were apparently seen kissing.She told The Sun newspaper: "Chris Brown and I are definitely just mates - I have known him since he was younger than 16. We were just talking.