Law enforcement sources told TMZ they were called to a residence Sunday night around 5:30 PM. No foul play is suspected in Jansen's death.
Hayden has yet to address her brother's unexpected passing.
Jansen appeared happy and healthy earlier this month, showcasing his talent as a graffiti artist. His last post was on February 6, in which he declared, "Graffiti is illegal."
He was Hayden's only sibling.
Jansen followed in his big sister's footsteps, appearing in projects like Even Stevens, Blue's Clues, Ice Age: The Meltdown, and more.
He even worked with Hayden in the early 2000s in Tiger Cruise and Racing Stripes. He continued his acting after linking up with his big sis, landing roles in Major Crimes and The Walking Dead.
He was linked to several projects at the time of his death.
The siblings were last seen together less than one month before his death. Jansen shared a photo of Hayden cutting his curly long locks on January 24.
"Not the first haircut she’s tried to give me," he teased.
Hayden and Jansen were extremely close, and their bond only got stronger during the pandemic.
In December 2020, the two escaped the city to spend some quality time in Pennsylvania. Jansen posted a snap showing the siblings rafting in the Delaware water gap.
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This is just the latest heartbreak Hayden has faced.
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“If he had … I would’ve said, ‘OK, that makes sense, I get it, I’ll come there to visit and stuff like that,” Hayden told Jada Pinkett Smith on Red Table Talk in November.
Calling the situation the “most heartbreaking thing I've ever had to do in my life," Hayden said it was the best decision for her daughter.
“It was the hardest thing I could do,” she said at the time. “But the best thing for my daughter was to make sure she was okay, take care of myself and make sure I could be a good mom to her. And sometimes that means letting go.”
Hayden revealed she had cut ties with her problematic boyfriend and quit booze in July — months before her brother's death.