Witt, 46, announced the news via a statement, saying she had asked a cousin nearby to check on her mother Dianne, 75, and father Robert, 75, at their property in Worcester, Massachusetts.
Officers late found the couple deceased on December 20 with no obvious causes of death, according to local newspaper Telegram & Gazette.
“I reached out to a cousin who lives close to my parents to check on them. Sadly, the outcome was unimaginable,” Witt said.
“I ask for some privacy at this time to grieve and to wrap my head around this turn of events, and this surreal loss.”
There had been reports the couple had been experiencing furnace problems and were using a space heater, however firefighters did not find any evidence of carbon monoxide in the home.
“There was no trauma,” Lieutenant Sean Murtha said in a statement.
The actress has previously paid tribute to her parents via gushing social media posts, describing her father as “wise and hilarious” in a Father’s Day post earlier this year.
“To my amazing dad, the wise and hilarious and always curious one, the greatest teacher, and the OG Witty,” Witt wrote in June. “I am deeply blessed in the dad department and I know that every single day.”
Witt also spoke warmly of her mother Dianne in a Mother’s Day post in 2018.
“#HappyMothersDay to all the mothers of this world,” Witt shared on Instagram, alongside photos of her mum.
“Thank you for bringing us into this place and for all that you do, every day, without even thinking twice. here is my beautiful mom when she came to visit me in #nashville two years ago.”
Witt made her acting debut in the 1984 movie Dune and has appeared in television shows including The Walking Dead, Orange is the New Black and Twin Peaks.
The TV star is also a singer and pianist and released an album, The Conduit, in September.
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