The X Factor judge and the Formula 1 racing driver, who went public with their romance back in 2007, are believed to have ended their relationship as their busy work schedules meant they just didn't get to see each other.
A source said: 'Nicole is just so heartbroken and completely devastated.'
Split: Nicole Scherzinger and Lewis Hamilton have ended their relationship after five years together
The sad news comes just a matter of weeks after 28-year-old Lewis hinted that he was planning to propose to Nicole, 34.
He said: 'We’ve been together for five years, which is quite a milestone really. But hopefully in the near future. Maybe before we get to six years.'
As they were: Nicole and Lewis were last pictured together at the Montreal Grand Prix in Canada on June 10th
Happier times: The pair began dating in 2007.
They are pictured in in 2008 at the 46664 Concert honouring Nelson
Mandela's 90th birthday
She said: 'I only go to a Grand Prix to support Lewis. I am in awe of Formula One because there is so much money, technology and talent, but as for the racing, it really is like trying to understand rocket science when I’m there, trackside.
‘For me there’s only ever one winner and a lot of people would agree with me on that – Lewis is the best.'
Radiant: Nicole looked in good spirits a she performed at the Summer Music Festival in Rome, Italy on June 27th
Rocking the stage: Nicole looked incredible in a metallic dress and thigh-high boots
But since recommitting to the X Factor
this year, Nicole has been kept busy with auditions in locations
including Glasgow, Dublin and London, while Lewis has been concentrating
on his racing career. The last time the couple were pictured together was at the Canadian Grand Prix in Montreal on June 10th.
Since then, Nicole has gone solo at various events including Wimbledon last week and the Summer Music Festival in Rome, Italy, where she put on a stunning performance last week.
Low profile: Lewis looked somewhat sombre as he
was pictured before the British Formula One Grand Prix at Silverstone
Circuit on Sunday
Failing equipment: Lewis said afterwards that he thinks he would have won the race if his left rear tyre hadn't failed
In July 2011 there was unconfirmed speculation the couple had become engaged.
The couple briefly split in January 2010 when they had been together for 20 months, before later reconciling.
Nicole and Lewis then split again in late 2011, before giving their relationship another go in early 2012.
Nicole is expected to make an appearance at the X Factor auditions in Cardiff later this week.
Working hard: Nicole has been kept busy with her
X Factor commitments on the judging panel alongside Sharon Osbourne,
Louis Walsh and Gary Barlow