Nicole Scherzinger and Lewis Hamilton break up after four years together

Nicole Scherzinger, 33, and Lewis Hamilton, 26, had broken up in January 2010 for the same reasons only to get back together a few weeks later.

This time, there has been no official statement, but according to sources close to the former couple, the two split due to distance.

The singer and X Factor judge lives in Los Angeles , while the Formula 1 driver travels constantly and has a house in Sweden .

“They’d been long distance for a long time and it’s just been hard,” an insider tells People.

“They both tried to make it work, but their careers kept them apart. So for now it’s over. They think this is what’s best. They’re definitely going to stay friends.”

Last July, the pair was the subject of engagement rumors but the Pussycat Dolls singer quickly denied the allegations.

Nicole and Lewis met four years ago in Munich , at the MTV Europe Music Awards.