Pussycat Dolls singer Nicole Scherzinger has split up from her boyfriend, Formula One racing driver Lewis Hamilton.They have ended their 20-month romance because they want to "focus fully" on their respective careers, reports thesun.co.uk."They have decided to go their separate ways. They want to focus fully on their careers and will remain close friends," reads a statement from their spokesperson.Friends of the couple are shocked because Scherzinger and Hamilton loved each other implicitly and were very happy."It's sad because they did love each other. When you saw them trackside together they were always laughing and Nicole would give him a little peck on the cheek before the race. But they had to be realistic. There was no way they would continue their careers and stay together - it was too stressful. No one else is involved - their careers just got in the way," said a friend of the couple, on condition of anonymity.Hamilton is based in Switzerland, while Scherzinger is in the US. In December, it was reported the couple hadn't seen each other in almost a month and even scrapped plans to spend Christmas together.The couple first met at the MTV Europe Music Awards in November 2007 and started dating in May 2008.
