They've been dating on/off since meeting on a movie set three years ago – and in recent months Cathriona White and Hollywood star Jim Carrey had rekindled their romance.
Tragically, however, reports from the US now say that Ms White has taken her own life.
She was aged just 28 and originally hailed from Cappawhite in Co Tipperary.
Police in Californian have told TMZ that after responding to a call last night, LAPD officers went to a local residence and discovered Cathriona's body.
It is believed that she was originally found by two concerned friends and a TMZ source added that Ms White left a suicide note addressed to Mr Carrey.
Cathriona had tweeted last Thursday: "Signing off Twitter, I hope I have been a light to my nearest and dearest."
US law enforcement reportedly believe she may have died from a drugs' overdose: pills were discovered next to her body.
She and 53-year-old Jim met in 2012 while she was working as a make-up artist.
They originally dated for more than a year before breaking-up. They then began seeing each other in May of this year but are believed to have split again in the last few days.
Cathriona trained as a beauty therapist in Ireland before moving to Hollywood in 2009.
Remember, if you need someone to talk to you can always contact the Samaritans for support. In Ireland, the organisation runs a 24-hour helpline on 116 123, or alternatively you can email email@example.com.