Ms White, 30, was a former girlfriend of Hollywood actor Jim Carrey, 53, who said the news of her death hit him like a “lightning bolt”.
It is understood friends of the Tipperary native became worried about Ms White earlier this week and went to her Los Angeles residence to check on her.
Law enforcement officials were called to the property at Sherman Oaks, California, at about 7.20pm local time on Monday night.
Members of Los Angeles Police Department said Ms White was pronounced dead at the scene approximately an hour and 20 minutes later.
While the cause of death is not yet confirmed, Ms White, who is from the Cappawhite area of Tipperary, is thought to have taken her own life.
A note was reportedly found at the scene, which is said to reference Ms White’s break-up with Carrey a few days previously. Sources say the relationship ended on September 24, the same day Ms White posted her final tweet.
“Signing off Twitter, I hope I have been a light to my nearest and dearest. (Peace and love) to you all,” she wrote.
Carrey said that he was “shocked” and “deeply saddened” by Ms White’s death.
“She was a truly kind and delicate Irish flower, too sensitive for this soil, to whom loving and being loved was all that sparkled,” he said in a statement.
“My heart goes out to her family and friends and to everyone who loved and cared about her.”
Ms White moved to LA in 2009 after training as a beauty therapist at the Limerick College of Further Education. She began dating Carrey in 2012 after they met on a film set.
Though the couple broke up after a few months, they rekindled their relationship last May .
Ms White worked on various comedy and drama projects, most notably The Online Gamer, Firefly, and Solitude.