Lewis Hamilton and Nicole Scherzinger have parted ways once more. Credit: Mike Marsland/WireImage

Nicole Scherzinger is now singing "Don't Cha" to her on-again, off-again boyfriend Lewis Hamilton. Sources confirm to Us Weekly that the two stars, who have had a famously rocky relationship, recently split once more. 

The Pussycat Dolls singer, 36, first started dating the British Formula One racer, 30, in 2007. They broke up multiple times over the years, seemingly for good in July 2013. They reconciled soon after, however, and engagement rumors started swirling. 

Us Weekly revealed in March 2014 that Scherzinger and Hamilton were not engaged, despite speculation to the contrary. Insiders tell Us that the lack of ring on the pop star's finger is the main reason for their most recent split.

"She wanted to get married now, he didn't," a source tells Us. "It was a problem caused by their age gap, not because he didn’t want to be with her."

Back in 2013, Hamilton discussed a possible future with his longtime love, telling The Sun, "We've been together for five years, which is quite a milestone, really," before adding that an engagement would be coming "hopefully in the near future... maybe before we get to six years."

Scherzinger, who is currently starring as Grizabella the Glamour Cat in a London West End revival of Andrew Lloyd Webber's Cats, has been spending time with her family this week. She took to Instagram this past weekend to share a photo of herself with her mother and grandmother, seeming to be in high spirits with her loved ones.

"Three generations kissed by the #Austriansunset," she captioned the image. "#sograteful to have my mom and tutu with me to witness God's awesomeness. #takemybreathaway."

Scherzinger and Hamilton have yet to comment on the split. The "Right There" singer was previously linked to musician Nick Hexum and reality star Talan Torriero, while Hamilton's former flames include his earlier longtime girlfriend Jodia Ma and beauty queen Lotta Hintsa