NEW YORK — “All That” alum Christy Knowings’ cause of death at the age of 46 has been revealed.

The former Nickelodeon star died of cardiac arrest on Aug. 11, four days after she was admitted to a hospital in Los Angeles, People reported, citing her death certificate. An unidentified family member previously told TMZ that she was hospitalized after suffering an asthma attack, which left her with brain damage, and that she was taken off life support not long after.

Acute hypoxic respiratory failure and status asthmaticus — or severe asthma — were also listed as contributing factors in her death, with asthma listed as the underlying cause, per People.

According to the Cleveland Clinic, acute hypoxic respiratory failure “prevents your lungs from filling up with air and causes dangerously low oxygen levels in your blood.”

Born in New York City, Knowings became a Nickelodeon staple at a young age, starring on the sketch comedy show for three seasons from 1997 to 2000 with the likes of Amanda Bynes, Nick Cannon and "SNL" player Kenan Thompson. She also appeared in three episodes of “Sesame Street” between 2008 and 2011 alongside her twin brother, Chris Knowings. And in 2020, she released a folk single called “To the World.”

Thompson took to social media to grieve the loss of his former co-star, sharing in a Facebook post that the news of her death “hit hard.”

“Rest well Christy!!! Never could have imagined this day!!” the "SNL" star wrote alongside a photo of Knowings.

“Sending so much love to her family!! She was a real one and one of the funniest people out here!!!” he continued. “Gonna miss you buddy!!! Show Christy Knowings some love y’all!!!”

©2026 New York Daily News. Visit nydailynews.com. Distributed by Tribune Content Agency, LLC.