A family source tells us Jansen died over the weekend in New York. His cause of death is currently unclear. Law enforcement sources tell us they got a call to a residence Sunday night around 5:30 PM. We're told there's no foul play suspected in Jansen's death.

Jansen, 5 years younger than Hayden, jumped onto the scene in the early 2000s, working on projects like "Even Stevens," "Blue's Clues," "Robots," and "Ice Age: The Meltdown." He also had a recurring role as Truman X in Nickelodeon's "The X's."

At one point, Jansen worked alongside Hayden in 2004's "Tiger Cruise" and 2005's "Racing Stripes."

He went on to star in Disney Channel original movies and made-for-TV Nickelodeon films, picking up a nomination for a Young Artist Award back in 2008 for his work on "The Last Day of Summer."

Jansen kept acting through the 2010s, working on shows like "Major Crimes" and "The Walking Dead." He also was attached to 5 more projects at the time of his death.

Jansen was only 28.