Lewis Hamilton and Nicole Scherzinger
Its all over.Reuters

Pop star Nicole Scherzinger and F1 ace Lewis Hamilton have split up for the fourth time.

According to reports, the former Pussycat Doll dumped the BBC Sports Personality of the Year after growing tired of his refusal to commit and put a ring on it.

An insider tells the Sun that while Scherzinger, 36, is keen to start a family, the Mercedes AMG driver, who recently won his second F1 title, is more dedicated than ever to his sport.

"It really is over this time," a source told The Sun. "They'd been fighting for months but things had got much worse.

"They spend so much time apart that things just became untenable," the insider added.

The Don't Cha hitmaker's persistence appeared to have paid off in March 2014 when it was reported that the couple were set to marry, but by November Hamilton had shrugged of the engagement reports, telling E! that marriage was not on the cards.

"I'm certainly feeling pressure, heat from family members," he told E! at Rihanna's Diamond Ball

"But Nicole's massively focused on her work the same as I am. We're happy just way we are."

The couple's surprise split come days after Hamilton alluded to the fact that starting a family at his peak could potentially be the nail in the coffin for his career.

"You hear about people who achieve a lot but then lose their focus and you wonder at what point does it fade off. I'm grateful that the fire is still there within me," he told whtimes.co.uk.

"I think subconsciously the taste of success spurs me on. I like that feeling and I want to feel it again and again."

Turbulent romance

The couple, who started dating after meeting in Munich, first split in 2011 claiming that their relationship had suffered as a result of "unworkable schedules".

"[They] have tried to make it work but realised it's just not happening so have called it a day once and for all," a source said at the time.

Although they rekindled their romance, they have broken up several times since due to the commitment issues.

When they split in July 2013 ahead of Scherzinger's judging stint on The X Factor, she confessed she was "an emotional wreck".

"I've not been dating," said Scherzinger. "That's not where my head's been at. At all. You have to be happy with yourself before you're happy with anyone else."