Hollywood star Connie Britton said she has “has no words” after the death of Hayden Panettiere, who she hailed as “bursting with brilliance”.

Panettiere, who starred as Britton’s fierce rival in country music drama Nashville, died aged 36 at her home in Greenville, South Carolina, on Sunday.

Police said the US actress, who had struggled with addiction and her mental health, was found unresponsive and in cardiac arrest, and there were “no signs of foul play or suspicious circumstances”.

A statement from Panettiere’s representatives on Monday said the star will be remembered by her family as an “incredible light” who brought “immeasurable love and joy to all who knew her”.

Tributes poured in with co-star Britton among those “heartbroken” by the loss.

The Emmy-nominated actress, who appeared alongside Panettiere in the US drama for nearly five years, shared images of her on set with her former co-star.

“This was Hayden. Bursting with brilliance, shining so bright,” she wrote.

The 59-year-old actress, also known for Friday Night Lights and American Horror Story, continued: “I have no words for this sad song.

“Just heartbreak.”

“I love you girl. Sleep easy now,” she added, accompanied by a broken heart emoji.

Charles Esten, who played Deacon Claybourne on Nashville, recalled the first time he met Panettiere in a lengthy social media tribute.

“We became fast friends, working very hard to play those 2 troubled Nashvillians, but always having fun and laughing a whole lot along the way,” he wrote.

“She was, of course, extraordinarily talented, infusing her larger-than-life character with all the heart, charisma, humor, whip-smart intelligence, and flat-out magic that were, alongside whatever troubles and pain she carried, a part of her own personal palette.”

Panettiere, who played Kirby Reed in Scream 4 and Scream VI, was also remembered fondly by co-stars from the horror franchise.

Emma Roberts, who appeared alongside Panettiere in films such as Scream 4 and The Architect, shared snaps of the two sharing an embrace. Roberts wrote: “Rest in peace my sweet friend.

“You are so loved and will be forever missed.”

Nico Tortorella, who also appeared in Scream 4, said: “I keep trying to write something, but there are too few words for you.”

Beneath a photo of himself with Panettiere, the 38-year-old actor added: “I love you, I miss you and I’m sorry.”

Actress Michelle Rodriguez told Variety she would remember the actress’s “curious spirit and how happy and joyous she is” while Scream writer and Dawson’s Creek creator Kevin Williamson shared a series of photos of Panettiere on his Instagram stories.

Kim Cattrall, who starred alongside Panettiere in Ice Princess, shared a picture of her with “sweet Hayden” and said she was “gone far too soon”.

Viola Davis, who featured alongside Panettiere in 2016 courtroom drama Custody, praised her as “an old, wise soul with such a deep heart” in a touching tribute on Instagram.

Bethany Joy Lenz, a long-time friend of Panettiere, said she was “crushed” by the death, and US actor Matt Lanter recounted working with her on sci-fi show Heroes.

“We always had a great time on set and tons of laughs… Man, just too young,” he wrote beneath a picture of them together.

Actor Tim Allen said in a post on X: “I am shocked and so sad as the passing of Hayden Panettiere. She played my daughter in the movie Joe Somebody. The fondest memories of that movie were moments around her. She is a wonder and my prayers are with her family.”

Brittany Snow, who played Panettiere’s on-screen sister for three years in the TV show Guiding Light, posted a throwback photo of the pair as children to her Instagram stories, captioning it: “I was lucky enough to play your sister for 3 years.

“I related to you so much in so many ways. Ways that I never even told you. Your talent was remarkable & so was your determination to be a bold, bright shining light. And you were.”

She said Panettiere was “always supportive, curious, funny and brave”, adding: “You will always be remembered undoubtedly for your undeniable strength and spirit.”

US actress and activist Alyssa Milano, famed for roles on Charmed and Who’s The Boss?, posted a lengthy tribute reflecting on the “courage” of Panettiere and praising her campaign work for animal rights, and for standing with Ukrainians amid the Euromaidan protests.

Milano added: “Her activism was not polished or performative. It was instinctive, human, sometimes messy, often vulnerable, and always sincere.

“She was willing to be uncomfortable, to be misunderstood, and to speak before the world was ready to listen.

“Hayden was a gifted actor, but that was only part of what she gave us. She used her voice. She showed up. She cared fiercely.

“I hope that is remembered too, the way she chose to stand in the world when it mattered.”

Alexa PenaVega, who starred in the Spy Kids films, paid tribute to Panettiere alongside fellow child stars, Michelle Trachtenberg and  Daveigh Chase, who both died earlier this year.

“These aren’t just names from my childhood,” she wrote on Instagram.

“They’re girls I grew up alongside, sharing a world that was exciting and also incredibly hard. We were kids navigating something so big, and not everyone had the foundation or support they deserved.