Former Pussycat Doll Nicole Scherzinger and boyfriend Lewis Hamilton, a Formula 1 racing driver, have split up after five years together.

The Sun reports that the most recent break-up between the duo was based on the struggles of a long-distance relationship.

“It’s so hard to keep up a relationship when they’re barely in the same country as each other," a source told the paper. “Both have supported each other in their careers and will continue to do so. But the nature of their work ultimately cost their relationship.”

According to Us Weekly, the 35-year-old singer and 28-year-old racer have been on-again, off-again in the past.

The couple, who originally started dating in 2007, first ended their relationship in 2010 but reunited four months later, according to Daily Mail Online, who received confirmation of the most recent split.

"It's not the first time they have broken up," a friend told Us. "But it feels like this time it's for good."

Ironically, Hamilton recently dropped hints of a possible proposal to Scherzinger.

"We’ve been together for five years, which is quite a milestone really," he said. "But hopefully in the near future. Maybe before we get to six years."

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