Hilary Duff Mourns Death Of 'Lizzie McGuire' Dad Robert Carradine

Hilary Duff is mourning the loss of her TV dad following the tragic death of Robert Carradine.

Duff, who played his onscreen daughter in "Lizzie McGuire," shared an emotional Instagram tribute Monday night after Carradine's family confirmed he died, taking his own life following a nearly two-decade battle with Bipolar Disorder.

"This one hurts," Duff wrote. "It's really hard to face this reality about an old friend. There was so much warmth in the McGuire family and I always felt so cared for by my on-screen parents. I'll be forever grateful for that. I'm deeply sad to learn Bobby was suffering. My heart aches for him, his family and everyone who loved him."

Jake Thomas, who played Matt McGuire, Carradine's son on the Disney Channel hit, also paid tribute.

"My heart hurts today," Thomas said. "I was fortunate to know Bobby for most of my life. And he was one of the coolest guys you could ever meet. Funny, pragmatic, sometimes cranky, always a little eccentric."

He continued, "He was a talented actor, musician and director. But more than anything, he was family. I have many fond memories of being with him and his family throughout my life. Good moments, challenging moments and lots of laughs in between."

Carradine's family described him as a "beacon of light" and acknowledged what they called his "valiant struggle" with mental illness, saying they hope his story helps break the stigma surrounding bipolar disorder.