Hayden Panettiere's 'Nashville' Costar Jonathan Jackson Posts Touching Tribute to Late Actress

Jonathan Jackson, who costarred with Hayden Panettiere on their hit TV show "Nashville," paid tribute to the late actress in an Instagram post, calling her a "bright light" and "amazingly gifted."

On Wednesday, Jackson uploaded a series of Instagram photos showing him and Hayden posing for smiling pics, including some from when they were working together on "Nashville."

In the show, Jackson played aspiring musician Avery Buckley who got married to Hayden's character, pop star Juliette Barnes. Off screen, the two were also close friends.

In addition to the photos, Jackson wrote an emotional message, kicking things off by saying he had "no words to express the loss of our beloved Hayden."

He went on ... "She had such a bright light within her. She was a sensitive soul. Incredibly funny and witty. Amazingly gifted, with a great sense of empathy and compassion.”

Then Jackson went into their history of working together, gushing about how Hayden was an "absolute joy" and always trustworthy. Jackson also said he and his wife, Lisa, will always have a special place in their hearts for Hayden, but all they feel now is shock and grief.

As we reported, Hayden died Sunday from a possible drug overdose in a Greenville, South Carolina, apartment, where she was staying.

Hayden's on-again, off-again boyfriend, Brian Hickerson, and his brother, Zach, called 911 after Zach discovered Hayden's body. The coroner has performed an autopsy, but the cause and manner of death are pending toxicology results.