Pop star NICOLE SCHERZINGER is in mourning following the death of her grandmother over the weekend (10-11Nov12).

The former Pussycat Dolls singer was devastated when her grandma died on Saturday morning (10Nov12), but she battled through her duties as a judge on the U.K. version of The X Factor on Saturday and Sunday night.

She then jetted back to the U.S. on Monday (12Nov12) with her racing driver boyfriend, Lewis Hamilton.

The star will attend her grandmother's funeral before returning to London to continue filming the TV talent contest next weekend (17-18Nov12).

A representative for Scherzinger tells Britain's Daily Mail newspaper, "Nicole had to return to the U.S. to attend her grandmother's funeral. Sadly, she passed away on Saturday morning.

"She did mention on the show that a couple of the songs were particularly poignant for her."

Fans of the show saw Scherzinger break down and cry during contestants' performances.